Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
  • C09J175/08—Polyurethanes from polyethers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
  • C08G18/0823—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups containing carboxylate salt groups or groups forming them
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
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  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0833—Manufacture of polymers containing ionic or ionogenic groups containing cationic or cationogenic groups together with anionic or anionogenic groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/10—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
  • C08G18/12—Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step using two or more compounds having active hydrogen in the first polymerisation step
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/2805—Compounds having only one group containing active hydrogen
  • C08G18/288—Compounds containing at least one heteroatom other than oxygen or nitrogen
  • C08G18/289—Compounds containing at least one heteroatom other than oxygen or nitrogen containing silicon
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3203—Polyhydroxy compounds
  • C08G18/3206—Polyhydroxy compounds aliphatic
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/34—Carboxylic acids; Esters thereof with monohydroxyl compounds
  • C08G18/348—Hydroxycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/48—Polyethers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/40—High-molecular-weight compounds
  • C08G18/48—Polyethers
  • C08G18/4825—Polyethers containing two hydroxy groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
  • C08G18/6666—Compounds of group C08G18/48 or C08G18/52
  • C08G18/6692—Compounds of group C08G18/48 or C08G18/52 with compounds of group C08G18/34
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
  • C08G18/75—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic
  • C08G18/758—Polyisocyanates or polyisothiocyanates cyclic cycloaliphatic containing two or more cycloaliphatic rings
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes
  • C09J175/12—Polyurethanes from compounds containing nitrogen and active hydrogen, the nitrogen atom not being part of an isocyanate group
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J7/00—Adhesives in the form of films or foils
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
  • G02F1/1675—Constructional details
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/165—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field
  • G02F1/166—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect
  • G02F1/167—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on translational movement of particles in a fluid under the influence of an applied field characterised by the electro-optical or magneto-optical effect by electrophoresis
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F2202/00—Materials and properties
  • G02F2202/28—Adhesive materials or arrangements

Definitions

• Electro-optic materials find uses in a wide variety of applications, for example, for use as adhesives.
• the adhesives may be utilized in electro-optic assemblies, wherein the electro- optic assemblies generally comprise a plurality of functional layers and can be used to form displays such as electrophoretic displays.
• Such assemblies may include a layer of electro- optic material, a front plane and a backplane.
• Electro-optic materials generally have at least two display states differing in at least one optical property (e.g., optical transmission, reflectance, luminescence) when different electric fields are applied to the material.
• Electro- optic displays can have attributes of good brightness and contrast, wide viewing angles, state bistablility, and low power consumption.
• electro-optic assemblies utilize an adhesive to adhere different layers together (e.g., the electro-optic material layer to the front plane and/or the backplane).
• adhesives are generally known in the art and may comprise, for example, hot-melt type adhesives and/or wet-coat adhesives, such as polyurethane-based adhesives.
• Adhesives generally require good strength of adhesion, while having certain properties (e.g., electrical properties, mechanical properties, thermal properties) that do not hinder the operation of the electro-optic display. However, there remains a need for adhesives with improved properties.
• the invention is a polyurethane adhesive material for use in electro-optic assemblies.
• the polyurethane adhesives typically include at least an end-capping cyclic carbonate group, however, they may include additional functional elements and/or cross- linkers.
• the adhesive is formed by two or more curing steps. Each curing step may comprise, for example, crosslinking of the adhesive, thermoplastic drying of the adhesive, end-capping the adhesive, chain-extending the adhesive, and/or combinations thereof such that the adhesive undergoes at least one cure in each curing step.
• polyurethane adhesive layers are disclosed for the use in electro-optic assemblies.
• the polyurethane a cyclic carbonate end- capping group.
• the adhesive comprises polyurethane and acrylic functional groups.
• the adhesive comprises a first reactive functional group, and a second reactive functional group, wherein at least one of the reactive functional groups has a dipole moment of greater than about 2 Debyes.
• FIGS. 1A-1E are schematic illustrations of electro-optic assemblies comprising an adhesive layer.
• FIG. 2 exemplifies end-capping reagents that may be used in the creation of adhesive layers for electro-optic assemblies.
• FIG. 3 exemplifies chain-extending reagents that may be used in the creation of adhesive layers for electro-optic assemblies.
• FIG. 4 exemplifies reactions that can be used for curing an adhesive layer in an electro-optic assembly.
• FIG. 5A is a plot of adjusted white state (WS) 30s image stability of experimental polyurethanes overcoated on an electro-optic layer.
• FIG. 5B is a plot of adjusted dark state (DS) 30s image stability traces of experimental polyurethanes overcoated on an electro-optic layer.
• FIG. 6 is a plot of adjusted 30s white state (WS) image stability for adhesive overcoated to an electro-optic layer with various levels of cyclic carbonate end groups (CCARB).
• FIG. 7 is a plot of drift in adjusted 30s WS L* versus mole % cyclic carbonate end cap group for adhesives overcoated to an electro-optic layer. FIG. 7 suggests an optimal range of cyclic carbonate to reduce 30s WS L* drift.
• FIG. 8 is a plot of drift in adjusted 30s WS image stability for pyrrolidone (HEP) and cyclic carbonate (CCARB) adhesives overcoated on an electro-optic layer.
• HEP pyrrolidone
• CCARB cyclic carbonate
• FIG. 9 is a plot of WS L* versus pulse length for a standard aqueous polyurethane dispersion adhesive (control) and a cyclic carbonate polyurethane adhesive with acid functionality (CCARB/Acid). Both adhesives were overcoated to an electro-optic layer compared with an aqueous polyurethane dispersion (control) laminated to the same ink, according to one set of embodiments;
• FIG. 10 is a plot of White State (WS) drift in L* (L*5WS) versus electrical stress time at 25 °C for polyurethane adhesive layers comprising a variety of functional groups.
• FIG. 11 is a plot of WS 30 second adjusted image stability traces for cyclic carbonate polyurethane (CCARB) coated at low and high dry adhesive coat weights compared to a commercially- available aqueous polyurethane dispersion adhesive coated at approximately 4 mil.
• CCARB cyclic carbonate polyurethane
• FIG. 12 shows Storage (G') and Loss (G") shear modulus curves at 1 Hz for hybrid polyurethane adhesives cured through stage I ("first cure”) and stage II (“second cure”).
• FIG. 13 is an SEM micrograph at lOOx magnification of an electrode/electro- optic layer/adhesive layer stack with a hybrid adhesive coated at 8 g/m 2 , after curing. This micrograph illustrates that the adhesive layer can be applied at good planarity and with minimal increase in the overall thickness of the stack.
• FIG. 14 is an SEM micrograph at lOOOx magnification of an electrode/electro- optic layer/adhesive layer stack with a hybrid adhesive coated at 8 g/m 2 , after curing.
• FIG. 15 shows exemplary schemes for reacting a polyurethane (PU) with crosslinkers.
• FIG. 16 is a plot of the Storage (G') and Loss (G") shear modulus curves at 1 Hz for uncured and cured (through stage II) cross-linked cyclic carbonate polyurethane (X- CCARB) adhesive.
• FIGS. 17A-17B are SEM micrographs at lOOx and lOOOx magnification, respectively, of electrode/electro-optic layer/adhesive layer stack with a cross-linked cyclic carbonate polyurethane coated at 7 g/m 2 , after curing, illustrating that the overall thickness of the electro-optic layer is increased only minimally with the inclusion of the adhesive.
• the invention includes a new class of polyurethane adhesive layers that are well-suited for incorporation into electro-optic assemblies, for example, encapsulated electrophoretic displays.
• the polyurethane adhesives typically include at least a cyclic carbonate group, however, they may include additional functional elements and/or cross- linkers.
• the adhesive is formed by two or more curing steps. Each curing step may comprise, for example, crosslinking of the adhesive, thermoplastic drying of the adhesive, end-capping the adhesive, chain-extending the adhesive, and/or combinations thereof such that the adhesive undergoes at least one cure in each curing step.
• the adhesive may comprise at least one type of end-capping reagent and/or at least one type of chain-extending reagent.
• the adhesive comprises two or more reactive functional groups (e.g., reactive functional groups configured to react with one or more curing species such that, for example, at least one of the two or more reactive functional groups forms a cured moiety such as a crosslink).
• the adhesive in some cases, comprises an acrylic.
• the adhesive is a hybrid adhesive comprising two or more types of adhesive materials (e.g., a hybrid adhesive comprising a polyurethane and an acrylic).
• the adhesive is formed by the curing of two or more adhesive materials under two different sets of conditions.
• the adhesive comprises an acrylic cured via thermoplastic drying and a polyurethane cured via reaction with the acrylic (e.g., via crosslinking with the acrylic).
• the method comprises curing an adhesive by reacting one or more reactive functional groups with one or more curing species (e.g., reacting the adhesive with a first curing species and, subsequently, reacting the adhesive with a second curing species).
• curing the adhesive may comprise crosslinking the adhesive by reacting one or more reactive functional groups with a curing species such as a crosslinking reagent. Reactive functional groups and types of curing species are described in more detail, herein.
• curing the adhesive may comprise crosslinking of the adhesive, thermoplastic drying of the adhesive, end-capping the adhesive, chain-extending the adhesive, and/or combinations thereof.
• curing the adhesive comprises a first curing step and a second curing step (e.g., wherein each curing step comprises reacting a reactive functional group with one or more curing species).
• a substrate e.g., a release layer, an electro-optic layer
• curing the adhesive comprises a first curing step and a second curing step (e.g., wherein each curing step comprises reacting a reactive functional group with one or more curing species).
• a substrate e.g., a release layer, an electro-optic layer
• the adhesives may be useful in a number of applications, including, but not limited to, materials for use in electro-optic assemblies (e.g., as adhesive layers).
• the electro-optic assemblies may form an electro-optic display such as an electrophoretic display.
• electro-optic assemblies generally comprise a plurality of functional layers including, but not limited to, a front plane electrode (e.g., which may comprise a polymeric film coated with a conductive material), a backplane electrode (e.g., which may comprise an electrode, circuitry, and/or a support layer) and an electro-optic material layer.
• the electro-optic material layer can comprise an electro-optic material having first and second display states differing in at least one optical property (e.g., optical transmission, reflectance, luminescence), the material being changed from its first to its second display state by application of an electric field to the material.
• the electro-optic material layer may include a plurality of capsules that are distributed in a binder.
• the capsules can include a clear fluid in which electrically- charged ink particles (e.g., black and white ink particles) are suspended. The ink particles translate within the capsule in response to electric fields to produce an image that is displayed.
• optical property is typically color perceptible to the human eye, it may be another optical property, such as optical transmission, reflectance, and luminescence or, in the case of displays intended for machine reading, pseudo-color in the sense of a change in reflectance of electromagnetic wavelengths outside the visible range.
• gray state is used herein in its conventional meaning in the imaging art to refer to a state intermediate two extreme optical states of a pixel, and does not necessarily imply a black-white transition between these two extreme states.
• EIDs electrophoretic displays
• the extreme states are white and deep blue, so that an intermediate "gray state” would actually be pale blue.
• the change in optical state may not be a color change at all.
• black and white may be used hereinafter to refer to the two extreme optical states of a display, and should be understood as normally including extreme optical states which are not strictly black and white, for example the aforementioned white and dark blue states.
• white and dark blue states may be used hereinafter to denote a drive scheme which only drives pixels to their two extreme optical states with no intervening gray states.
• electro-optic displays are known.
• One type of electro-optic display is a rotating bichromal member type as described, for example, in U.S. Patents Nos. 5,808,783; 5,777,782; 5,760,761; 6,054,071 6,055,091; 6,097,531; 6,128,124; 6,137,467; and 6,147,791 (although this type of display is often referred to as a "rotating bichromal ball" display, the term "rotating bichromal member" is preferred as more accurate since in some of the patents mentioned above the rotating members are not spherical).
• Such a display uses a large number of small bodies (typically spherical or cylindrical) which have two or more sections with differing optical characteristics, and an internal dipole. These bodies are suspended within liquid-filled vacuoles within a matrix, the vacuoles being filled with liquid so that the bodies are free to rotate. The appearance of the display is changed by applying an electric field thereto, thus rotating the bodies to various positions and varying which of the sections of the bodies is seen through a viewing surface.
• This type of electro-optic medium is typically bistable.
• an electrochromic medium for example an electrochromic medium in the form of a nanochromic film comprising an electrode formed at least in part from a semi-conducting metal oxide and a plurality of dye molecules capable of reversible color change attached to the electrode; see, for example O'Regan, B., et al., Nature 1991, 353, 737; and Wood, D., Information Display, 18(3), 24 (March 2002). See also Bach, U., et al., Adv. Mater., 2002, 14(11), 845. Nanochromic films of this type are also described, for example, in U.S. Patents Nos. 6,301,038; 6,870,657; and 6,950,220. This type of medium is also typically bistable.
• Electrophoretic displays can have attributes of good brightness and contrast, wide viewing angles, state bistability, and low power consumption when compared with liquid crystal displays. Nevertheless, problems with the long-term image quality of these displays have prevented their widespread usage. For example, particles that make up electrophoretic displays tend to settle, resulting in inadequate service-life for these displays.
• electrophoretic media require the presence of a fluid.
• this fluid is a liquid, but electrophoretic media can be produced using gaseous fluids; see, for example, Kitamura, T., et al., "Electrical toner movement for electronic paper- like display", IDW Japan, 2001, Paper HCSl-1, and
• encapsulated electrophoretic and other electro-optic media comprise numerous small capsules, each of which itself comprises an internal phase containing electrophoretically-mobile particles in a fluid medium, and a capsule wall surrounding the internal phase.
• the capsules are themselves held within a polymeric binder to form a coherent layer positioned between two electrodes.
• the technologies described in the these patents and applications include:
• PDEPID polymer-dispersed electrophoretic display
• the electrophoretic medium comprises a plurality of discrete droplets of an electrophoretic fluid and a continuous phase of a polymeric material
• the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be regarded as capsules or microcapsules even though no discrete capsule membrane is associated with each individual droplet; see for example, the aforementioned U.S. Patent No. 6,866,760.
• such polymer-dispersed electrophoretic media are regarded as sub-species of encapsulated electrophoretic media.
• a related type of electrophoretic display is a so-called "microcell
• electrophoretic display In a microcell electrophoretic display, the charged particles and the fluid are not encapsulated within microcapsules but instead are retained within a plurality of cavities formed within a carrier medium, typically a polymeric film. See, for example, U.S. Patents Nos. 6,672,921 and 6,788,449, both assigned to Sipix Imaging, Inc.
• electrophoretic media are often opaque (since, for example, in many electrophoretic media, the particles substantially block transmission of visible light through the display) and operate in a reflective mode
• many electrophoretic displays can be made to operate in a so-called "shutter mode" in which one display state is substantially opaque and one is light-transmissive. See, for example, U.S. Patents Nos. 5,872,552; 6,130,774;
• An encapsulated electrophoretic display typically does not suffer from the clustering and settling failure mode of traditional electrophoretic devices and provides further advantages, such as the ability to print or coat the display on a wide variety of flexible and rigid substrates.
• printing is intended to include all forms of printing and coating, including, but without limitation: pre-metered coatings such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating such as knife over roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silk screen printing processes; electrostatic printing processes; thermal printing processes; ink jet printing processes; electrophoretic deposition (See U.S. Patent No. 7,339,715); and other similar techniques.)
• pre-metered coatings such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating
• roll coating such as knife over roll coating, forward and reverse roll coating
• gravure coating dip coating
• spray coating meniscus coating
• spin coating brush coating
• bistable electro-optic displays act, to a first approximation, as impulse transducers, so that the final state of a pixel depends not only upon the electric field applied and the time for which this field is applied, but also upon the state of the pixel prior to the application of the electric field.
• the pixels are arranged in a two-dimensional array of rows and columns, such that any specific pixel is uniquely defined by the intersection of one specified row and one specified column.
• the sources of all the transistors in each column are connected to a single column electrode, while the gates of all the transistors in each row are connected to a single row electrode; again the assignment of sources to rows and gates to columns is conventional but essentially arbitrary, and could be reversed if desired.
• the row electrodes are connected to a row driver, which essentially ensures that at any given moment only one row is selected, i.e., that there is applied to the selected row electrode a voltage such as to ensure that all the transistors in the selected row are conductive, while there is applied to all other rows a voltage such as to ensure that all the transistors in these non-selected rows remain non-conductive.
• the column electrodes are connected to column drivers, which place upon the various column electrodes voltages selected to drive the pixels in the selected row to their desired optical states.
• aforementioned voltages are relative to a common front electrode which is conventionally provided on the opposed side of the electro-optic medium from the non-linear array and extends across the whole display.)
• the selected row is deselected, the next row is selected, and the voltages on the column drivers are changed so that the next line of the display is written. This process is repeated so that the entire display is written in a row-by -row manner.
• An adhesive layer may be used to join together layers of the display.
• the front plane electrode and/or the backplane electrode are adhered to the electro-optic material layer using an adhesive layer.
• the electro-optic material layer also may be referred to as electro-optic medium, ink or ink layer.
• the adhesive may comprise a polymer (e.g., polyurethane) which may be thermally, chemically, and/or optically cured.
• the adhesive comprises a polyurethane comprising select end-capping reagents which results in certain performance enhancements.
• the end-capping reagent comprises a cyclic carbonate.
• the end-capping reagents comprise a first type of end-capping reagent and a second type of end-capping reagent.
• the use of adhesives comprises two or more cured moieties (formed by two or more curing steps) may offer several advantages over traditional adhesives.
• improved rheology of the adhesive system enables adhesive coatings on a layer (e.g., electro-optic layer such as an air-dried side that has a relatively rougher surface as compared to the smooth, release side ("SSL")) resulting in a decreased coat weight, decreased ink-adhesive coating thickness, improved display resolution, improved low temperature dynamic range, thinner coatings for flexible applications, and reduced formation of voids and/or defects as compared to the use of adhesives with only one cured moiety.
• electro-optic layer such as an air-dried side that has a relatively rougher surface as compared to the smooth, release side (“SSL”)
• improved performance of an electro-optic assembly is observed for embodiments where adhesive is dual-cured to form an electro-optic assembly using as compared to being applied by hot melting, including, but not limited to, reduced white state L* loss over time, increased dynamic range, improved low temperature operation (e.g., improved dynamic range), and increased volume resistivity.
• traditional adhesives may suffer from poor low temperature performance, poor rheology, and may have electrical properties (e.g., resistivity) which reduces the functionality of the electro-optic material layer (e.g., reduced switching efficiency).
• cured moiety generally refers to a physical connection (e.g., a covalent bond, a non-covalent bond, etc.) between two or more polymer backbones.
• backbone is given its typical meaning in the art and generally refers to a series of covalently bound atoms that together create a continuous chain forming the polymer, and generally does not refer to any side chains (e.g., branches) or cross-linked groups.
• the cured moiety may comprise, in some cases, a crosslink (e.g., the reaction of two or more reactive functional groups with a cros slinking reagent).
• the cured moiety is formed by the reaction of a reactive functional group, a curing species such as a crosslinking reagent, and a second reactive functional group, such that the first reactive functional group and the second reactive functional group are connected by the curing species.
• the first reactive functional group and the second reactive functional group are the same type of reactive functional group.
• the first reactive functional group and the second reactive functional group may be different types of reactive functional groups.
• the curing species is connected to the first reactive functional group and/or the second reactive functional group via formation of a bond, such as an ionic bond, a covalent bond, a hydrogen bond, Van der Waals interactions, and the like.
• the covalent bond may be, for example, carbon-carbon, carbon-oxygen, oxygen- silicon, sulfur-sulfur, phosphorus-nitrogen, carbon-nitrogen, metal-oxygen, or other covalent bonds.
• the hydrogen bond may be, for example, between hydroxyl, amine, carboxyl, thiol, and/or similar functional groups.
• the cured moiety is formed by the thermoplastic drying of an adhesive material such that two or more polymer backbones interact to form a bond (e.g., through intermolecular forces such as hydrogen bonding, dipole-dipole, etc.).
• an acrylic (e.g., polyacrylic) polymer may be dried (e.g., via the application of heat to the adhesive material(s)) such that two or more reactive functional groups on the polymer backbone undergo thermoplastic reaction (e.g., by the removal of water and the increase in the glass transition temperature (Tg) of the adhesive material (e.g., for an amorphous adhesive material) and the formation of a bond between the two reactive functional groups) thereby forming a cured moiety connecting the original polymer backbones.
• thermoplastic reaction e.g., by the removal of water and the increase in the glass transition temperature (Tg) of the adhesive material (e.g., for an amorphous adhesive material) and the formation of a bond between the two reactive functional groups
• a polyurethane-acrylic hybrid adhesive is cured in a first step by thermoplastic drying, followed by curing in which crosslinking occurs between a reactive species on the polymer backbone of the polyurethane with a reactive species on the acrylic backbone.
• the adhesive comprises two or more types of cured moieties.
• the adhesive comprises a first type of cured moiety comprising a first crosslink (formed by the reaction of a first crosslinking reagent with two or more reactive species) and a second type of cured moiety comprising a second crosslink (formed by the reaction of a second crosslinking reagent with two or more reactive species).
• the first and second crosslinking reagents may be, in some cases, the same or different.
• the adhesive may comprise a first type of cured moiety comprises a first crosslink and a second type of cured moiety comprising a thermoplastic linkage.
• curing species generally refers to a compound that facilitates the reaction between two or more reactive functional groups such that the reactive functional groups are connected.
• the curing species may be, in some cases, a crosslinking reagent.
• the reaction of a curing species with two or more reactive functional groups may form a cured moiety, as described above.
• an electro-optic assembly 100 comprises a backplane electrode 110, a front plane electrode 130, and an electro-optic material layer 120. As noted above, different layers of the assembly can be joined together with an adhesive layer 140.
• backplane electrode 110 is adhered to the electro-optic material layer by adhesive layer 140.
• front plane electrode 130 is adhered to electro-optic material layer 120 by adhesive layer 142, which may comprise the same or different adhesive as adhesive layer 140.
• an electro-optic material layer 125 may comprise capsules 150 and a binder 160, described in more detail below.
• the capsules 150 may encapsulate one or more particles that can be caused to move with the application of an electric field across the electro-optic material layer 125.
• front plane electrode 130 may be directly adjacent electro-optic material layer 125 and backplane electrode 110 is adhered to the electro-optic material layer by adhesive layer 140.
• backplane electrode 110 may be adhered to electro-optic material layer 125 by adhesive layer 140 and front plane electrode 130 may be adhered to electro-optic material layer 125 by adhesive layer 142.
• front plane electrode 130 may be adhered to electro- optic material layer 125 by adhesive layer 140 and backplane electrode 110 may be adhered to electro-optic material layer 125 by adhesive layer 142.
• the adhesive layer may be used to adhere any type and number of layers to one or more other layers in the assembly, and the assembly may include one or more additional layers that are not shown in the figures. Additionally, while FIGS. 1C-1E illustrate an encapsulated electro-optic medium, the adhesive layers are useful in a variety of electro-optic assemblies, such as liquid crystal, frustrated internal reflection, and light-emitting diode assemblies.
• the adhesive layers may include additional components.
• suitable components include other polyurethanes, acrylics, alkyds, epoxies, aminos, and siloxanes.
• the adhesive layer may comprise two or more types of similar adhesive materials (e.g., two types of acrylics, an acrylic and an alkyd, a polyurethane and a siloxane, two types of polyurethanes, a polyurethane and an acrylic).
• the adhesive is provided in the form of a dispersion (e.g., an aqueous dispersion).
• a dispersion e.g., an aqueous dispersion
• an adhesive dispersion may be used directly in a coating process and/or by solutions of reactive monomers in dispersions or solutions of adhesives to form an adhesive layer as described herein.
• the aqueous dispersion comprises water which may be removed (e.g., via the application of heat) after deposition of the adhesive to one or more surfaces.
• polyurethanes are prepared via a polyadditional process involving a diisocyante.
• polyurethanes include polyether polyurethanes, polyester polyurethanes, polyether polyureas, polyureas, polyester polyureas, polyester polyureas, polyisocyanates (e.g., polyurethanes comprising isocyanate bonds), and polycarbodiimides (e.g., polyurethanes comprising carbodiimide bonds).
• the polyurethane contains urethane groups.
• the polyurethanes utilized in the assemblies and methods described herein may be prepared using methods known in the art.
• an isocyanate-terminated polyurethane is formed by reaction of at least one diisocyanate compound with a secondary reagent comprising at least two groups which are capable of reacting with an isocyanate group (e.g., a polyol).
• the polyurethane is a linear polymer formed via reaction of a diisocyanate compound and a secondary reagent comprising two groups which are capable of reacting with an isocyanate group (e.g., a diol).
• the terminal isocyanate groups may be deactivated via reaction with a terminating reagent, respectively, thereby forming a terminated polyurethane (e.g., such that the polyurethane and/or terminal isocyanate groups do not undergo further reaction).
• a terminating reagent e.g., such that the polyurethane and/or terminal isocyanate groups do not undergo further reaction.
• the terminal isocyanate groups may be end-capped via reaction with one or more end-capping reagents, thereby forming an end- capped polyurethane.
• the isocyanate-terminated polyurethane may be neutralized via reaction with a neutralizing reagent, such that the polyurethane may be dispersed into water such as when stabilized by ionic groups.
• the molecular weight of polyurethane may be controlled by the addition of at least one type of end-capping reagent. End-capping reagents are described in more detail below and may also be used in the preparation of other adhesives.
• the polyurethane e.g., isocyanate-terminated polyurethane, end-capped polyurethane, and/or neutralized polyurethane
• the polyurethane may be formed by a providing a mixture of at least one diisocyanate, a secondary reagent comprising at least two groups which are capable of reacting with an isocyanate group, and one or more end-capping reagents, and substantially simultaneously reacting the mixture.
• the one or more end-capping reagents are added after reacting a mixture comprising at least one diisocyanate and a second reagent comprising at least two groups which are capable of reacting with an isocyanate group.
• the end-capping reagents may be added during the reaction of the mixture and/or after the reaction of the mixture (e.g., after neutralization of the reaction, as described herein).
• the isocyanate-terminated polyurethane is formed via reaction of at least one diisocyanate compound with at least one difunctional polyol or at least one multifunctional polyol.
• the polyol is a diol (e.g., an oligomer with two alcohol terminal groups, a polymer with two alcohol terminal groups).
• the reaction is carried out using a stoichiometric excess of the at least diisocyanate compound, thereby aiding in the formation of an isocyanate-terminated polyurethane.
• the ratio of the at least one diisocyante compound to the diol is between about 2:1 and about 1:2, or between about 1.5:1 and about 1:1.5, or about 1:1.
• Those of ordinary skill in the art will be able to adjust this ratio when using polyols which include more than two reactive -OH groups.
• More than one type of diisocyanate compound may be utilized, for example, two types, three types, or four types of diisocyanate compounds.
• more than one type of diol (or polyol) may be utilized, for example, two types, three types, or four types of diols. In some embodiments, three types of diols are utilized.
• diisocyanate is given its ordinary meaning in the art and is used to describe a linear, cyclic, or branch-chained hydrocarbons, including aromatic, cycloaliphatic, and aliphatic hydrocarbons having two free isocyanate groups.
• diisocyanate compounds include 4,4-methylenebis(cyclohexylisocyanate) (H12MDI), ⁇ , ⁇ , ⁇ , ⁇ -tetramethylxylene diisocyanate, 3,5,5-trimethyl- l-isocyanato-3- isocyanatomethylcyclohexane isophorone diisocyanate and derivatives thereof,
• tetramethylene diisocyanate hexamethylene diisocyanate (HDI) and derivatives thereof, 2,4- toluene diisocyanate, 2,6-toluene diisocyanate, isophorone diisocyanate, m-isopropenyl- ⁇ , ⁇ - dimethylbenzyl isocyanate, benzene l,3-bis(l-iscyanato-l-methylethyl, 1-5 naphthalene diisocyanate, phenylene diisocyanate, trans-cyclohexane-l,4-diisocyanate, bitolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl dimethyl methane diisocyanate, di- and tetraalkyl diphenyl methane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylene diis
• the secondary reagent comprises a polyamine or a diamine.
• the secondary reagent comprises a thiol group.
• polyol is given its ordinary meaning in the art and refers to any organic compound having two or more hydroxyl groups, wherein the hydroxyl groups are capable of reacting with an isocyanate group.
• the polyol utilized is a diol.
• the diol is a difunctional polyol.
• the diol is a difunctional oligomer with two reactive alcohol groups.
• Non- limiting examples of difunctional polyols include polyethylene glycol, polypropylene glycol (PPO), polytetramethylene glycol.
• the molecular weight of polyol may vary. In some embodiments, the molecular weight (Mn) is less than about 5000, or less than about 3000, or between about 500 and about 5000, or between about 500 and about 4000, or between about 500 and about 3000.
• At least one diol comprises an ionic group (e.g., a carboxylic acid group).
• the ionic group may be used to stabilize the polyurethane (e.g., when dispersed in water) and/or may be utilized for crosslinking.
• diols comprising an ionic group include dimethylolpropionic acid (DMPA),
• dimethylolbutanoic acid dimethylolpentanoic acid, diethylolpropionic acid,
• diethylolbutanoic acid diethylolbutanoic acid, l,4-dihydroxy-2-butane sulfonic acid, l,5-dihydroxy-2-pentane sulfonic acid, l,5-dihydroxy-3-pentane sulfonic acid, l,3-dihydroxy-2-propane sulfonic acid, dimethylolethane sulfonic acid, N-methyldiethanolamine, N-ethyidiethanolamine, N- propyidiethanolamine, N,N-dimethyl-2-dimethylolbutylamine, N,N-diethyl-2- dimethylolbutylamine, N,N-dimethyl-2-dimethylolpropylamine.
• the ionic group is a carboxylic acid group.
• diols comprises a carboxylic acid group include dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolpentanoic acid, diethylolpropionic acid, and diethylolbutanoic acid, polyester diol, and other polymeric carboxylic acid groups.
• the diol comprising an ionic group is dimethylolpropionic acid.
• the secondary reagent may comprise a first type of secondary reagent (e.g., a first type of diol) and a second type of secondary reagent (e.g., a second type of diol).
• the secondary reagent may comprise a first type of secondary reagent (e.g., a first type of diol), a second type of secondary reagent (e.g., a second type of diol), and a third type of secondary reagent (e.g., a third type of diol).
• the first type of diol is a difunctional polyol (e.g., polypropylene glycol)
• the second type of diol comprises an ionic group (e.g., a carboxylic acid group, such as DMPA)
• the third type of diol may function as a non-ionic stabilizer.
• the adhesive comprises an acrylic.
• the adhesive comprises two or more types of adhesives (e.g., a polyurethane and an acrylic).
• Such adhesive mixtures may be formed by physically blending at least two components which may be any combination of solution or dispersed materials in aqueous or solvent based media.
• the hybrid adhesives may also be formed by synthetic polymerization processes where one component is polymerized in the presence of a second polymeric component, or both polymers may be formed simultaneously.
• the hybrid adhesives may be formed by emulsifying polymerizable monomers in an adhesive dispersion that is used directly in the coating process, and/or by solutions of reactive monomers in dispersions or solutions of adhesives.
• polymerization of the monomers may occur at the primary or secondary stages (i.e. cures) and may also help in ink surface void filling and particle coalescence (e.g., if using dispersions).
• the adhesive material comprises two or more reactive functional groups.
• the reactive functional groups may be positioned as end groups, along the backbone or along chains extended from the backbone.
• Reactive functional groups generally refer to a chemical group (present on the adhesive) configured to react with one or more curing species (e.g., a crosslinking reagent, a chain-extending reagent).
• the reactive functional group reacts with a curing species to form a cured moiety such as a crosslink, a thermoplastic linkage, a bond between two types of adhesive materials, or the like.
• a reactive functional group may react with a curing species such as a crosslinking reagent to form a crosslink.
• a reactive functional group may be configured to react with another reactive functional group under a particular set of conditions (e.g., at a particular range of temperatures).
• a reactive functional group my react under certain conditions such that the adhesive material undergoes thermoplastic drying.
• Non-limiting examples of reactive functional groups include hydroxyls, carbonyls, aldehydes,
• the curing steps described herein do not generally refer to the formation of an adhesive material (e.g., polymerization of an adhesive backbone such as a polyurethane backbone) but the further reaction of an adhesive material such that the adhesive material forms crosslinks, undergoes thermoplastic drying, or the like such that the adhesive undergoes a substantial change in mechanical properties, viscosity, and/or adhesiveness.
• an adhesive material e.g., polymerization of an adhesive backbone such as a polyurethane backbone
• the further reaction of an adhesive material such that the adhesive material forms crosslinks, undergoes thermoplastic drying, or the like such that the adhesive undergoes a substantial change in mechanical properties, viscosity, and/or adhesiveness.
• one or more of the elastic modulus, the viscosity, and the adhesiveness of the adhesive material after curing may increase by between about 5% and about 1000% as compared to the elastic modulus, the viscosity, and/or the adhesiveness of the adhesive material prior to curing.
• one or more of the elastic modulus, the viscosity, and the adhesiveness of the adhesive material after curing may increase by at least about 10%, at least about 20%, at least about 50%, at least about 100%, at least about 200%, or at least about 500% as compared to the elastic modulus, the viscosity, and/or the adhesiveness of the adhesive material prior to curing.
• the reactive functional group is present on the backbone of the adhesive.
• the reactive functional group may be present on the diisocyante group and/or on the polyol group reacted to form the polyurethane.
• the reactive functional group is present on an end- capping reagent.
• the isocyanate-terminated polyurethane may be end-capped by reaction with at least one type of end-capping reagent, thereby forming an end-capped adhesive (e.g., end-capped polyurethane).
• an end-capping reagent may aid in controlling the molecular weight of the adhesive.
• more than one type of end-capping reagent may utilized, for example, two types, three types, or four types of end-capping reagent. The total amount of end-capping agents may be adjusted to produce an adhesive which is either partially or completely end-capped.
• partial end-capping may be achieved by reaction of the adhesive (e.g., the isocyanate-terminated polyurethane) with less than a 100% stoichiometric amount of the end-capping reagent(s).
• the adhesive e.g., the isocyanate-terminated polyurethane
• 50 to 100% of the polyurethane is end-capped.
• following reaction of the isocyanate-terminated polyurethane with the end-capping reagent at least about 50%, at least about 60%, at least about 75%, at least about 80%, or at least about 90% of the polyurethane is terminated with an end-cap group.
• less than or equal to 100%, less than or equal to about 90%, less than or equal to about 80%, less than or equal to about 75%, or less than or equal to about 60% of the polyurethane is terminated with an end-cap group. Combinations of the above-referenced ranges are also possible (e.g., between about 50% and 100%, between 50% and 75%, between 60% and 90%, between 75% and 100%).
• End-capped adhesives such as polyurethanes may be neutralized and/or chain-extended, as described in more detail herein.
• the end-capping reagent comprising the reactive functional group.
• suitable end-capping reagents e.g., comprising reactive functional groups are shown in FIG. 2 and are described in more detail, below.
• At least one of the types of end-capping reagent includes a compound having the structure as in Formula (I): wherein R 1 is selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted heteroalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted nitrile, optionally substituted carbamate, optionally substituted imidazolium, optionally substituted pyrrolidone, optionally substituted carbonate, optionally substituted acrylate, optionally substituted ether, optionally substituted ester, optionally substituted halide, optionally substituted acid, optionally substituted silane, optionally substituted thiol, L is a linking group, optionally absent, and represents the location of a bond to the polyurethane.
• R 1 is selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted heteroalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted nitrile,
• linking groups include optionally substituted alkylenes, optionally substituted heteroalkylenes, optionally substituted arylenes, and optionally substituted heteroarylenes.
• R 1 is hydrogen.
• R 1 comprises the reactive functional group.
• L comprises the reactive functional group.
• an end-capping reagent comprising Formula (I) is associated with a polyurethane via reaction of a isocyanate-terminated polyurethane and an end-capping reagent comprising Formula (II):
• Q is hydroxyl (HO-) or amino (H 2 N-)
• HO- hydroxyl
• H 2 N- amino
• the end-capping reagent is n-butanol.
• At least one of the types of end-capping reagent includes a nitrile resulting in an end-capped polyurethane comprising a nitrile.
• nitrile is given its ordinary meaning in the art and generally refers to a molecular group containing at least one type of cyanide group.
• the end-capping reagent comprising a nitrile compr
• Formula (III) comprises Formula (IV):
• an end-capping reagent comprising Formula (III) or (IV) is associated with a polyurethane via reaction of a isocyanate- terminated polyurethane and an end-capping reagent comprising Formula (V):
• the end-capping reagent is 3-hydroxypropionitrile.
• At least one of the types of end-capping reagent includes a carbamate resulting in an end-capped polyurethane comprising a carbamate.
• carbamate is given its ordinary meaning in the art and generally refers to a molecular group containing at least one type of -OOCNH2 group.
• the end- capping reagent comprising a carbamate comprises Formula (VI):
• R 2 comprises the reactive functional group.
• L comprises the reactive functional group.
• Formula (VI) comprises Formula (VII):
• an end-capping reagent comprising Formula (VI) or (VII) is associated with a polyurethane via reaction of a isocyanate- terminated polyurethane and an end-ca in rea ent com risin Formula (VIII): wherein Q is hydroxyl or amino, L is described above as in Formula (I), and R 2 is described above as in Formula (VI).
• the end-capping reagent is hydroxyethyl carbamate.
• At least one of the types of end-capping reagent includes an imidazole resulting in an end-capped polyurethane comprising a imidazole.
• the end-capping reagent comprising a imidazole comprises Formula (IX):
• Formula (IX) comprises Formula (X): wherein m is 1-10. In some embodiments, m is 1-5, or 1-3, or 1, or 2, or 3, or 4, or 5. In some embodiments, m is 1. In some embodiments, an end-capping reagent comprising Formula (IX) or (X) is associated with a polyurethane via reaction of a isocyanate-terminated polyurethane and an end-capping reagent comprising Formula (XI): Q N + — R 2
• the end-capping reagent is 2-hydroxyethylmethyl imidazolium.
• At least one of the types of end-capping reagent includes a cyclic carbonate resulting in an end-capped polyurethane comprising an end- capping reagent comprising a cyclic carbonate.
• cyclic carbonate is given its ordinary meaning in the art and refers to a molecular group containing at least one type of cyclic carbonate oligomer, e.g., dimer, trimer, tetramer, etc.
• the end- capping reagent comprising a c stunt carbonate comprises Formula (XII):
• R 2 is described above as in Formula (VI)
• L is described above as in Formula (I)
• n is 1-4
• ⁇ represents the location of a bond to the polyurethane.
• R 2 is hydrogen.
• n is 1.
• n is 2.
• L is optionally substituted alkylene.
• Formula (XII) comprises Formula (XI
• an end-capping reagent comprising Formula (II) or (III) is associated with a polyurethane via reaction of a isocyanate-terminated polyurethane and an end-capping reagent comprising Formula (XIV):
• m is as described above in connection with Formula (XIII).
• m is 1.
• the end-capping reagent is glycerin carbonate.
• an end-capping reagent comprises a pyrrolidone.
• the end-capping reagent comprising a pyrrolidone comprises Formula (XVI):
• each R 2 is the same or different and is selected from the group consisting of hydrogen, optionally substituted alkyl, optionally substituted heteroalkyl, optionally substituted aryl, optionally substituted heteroaryl, optionally substituted halide, and optionally substituted hydroxyl
• M is a linking group, optionally absent, and— represents the location of a bond to the polyurethane.
• Non-limited examples of linking groups include optionally substituted alkylene and optionally substituted heteroalkylene.
• each R 2 is hydrogen.
• M is optionally substituted alkylene.
• Formula (XVI) comprises Formula (XVII):
• M comprises the reactive functional group.
• an end-capping reagent comprising Formula (XVI) or (XVII) is associated with a polyurethane via reaction of a isocyanate-terminated polyurethane and an end-ca ing reagent comprising Formula (XVIII):
• the compound of Formula (XVIII) comprises Formula (XIX):
• r is as described above in connection with Formula (XVII).
• r is 2.
• the end-capping reagent is 2-hydroxyethyl pyrrolidone.
• At least one of the types of end-capping reagent includes an acrylate resulting in an end-capped polyurethane comprising an acrylate.
• the end-capping reagent comprising an acrylate comprises Formula (XX):
• Formula (XX) comprises Formula (XXI):
• an end-capping reagent comprising Formula (XX) or (XXI) is associated with a polyurethane via reaction of a isocyanate- terminated polyurethane and an end-capping reagent comprising Formula (XXII):
• the end-capping reagent is 2-hydroxyethyl acrylate or 2- hydroxyethyl methacrylate.
• At least one of the types of end-capping reagent includes an ether resulting in an end-capped polyurethane comprising an ether.
• the end-capping reagent comprisin an ether comprises Formula (XXIII): (XXIII)
• Formula (XXIII) comprises Formula (XXIV):
• an end-capping reagent comprising Formula (XXIII) or (XXIV) is associated with a polyurethane via reaction of a isocyanate- terminated polyurethane and an end-ca ing reagent comprising Formula (XXV):
• the end-capping reagent is 2-ethoxyethanol.
• At least one of the types of end-capping reagent includes a halide resulting in an end-capped polyurethane comprising an halide.
• the end-capping reagent comprising an halide comprises Formula (XXVI):
• X is a halogen (e.g., F, CI, Br, I)
• Y is optionally substituted arylene, optionally substituted Ci-io alkylene, or optionally substituted alkylene oxide.
• Y comprises the reactive functional group.
• X comprises the reactive functional group.
• an end-capping reagent comprising Formula (XXVI) or (XXVII) is associated with a polyurethane via reaction of a isocyanate- terminated polyureth a (XXVIII):
• the end-capping reagent is 4-chlorobenzyl alcohol.
• an end-capping reagent comprising Formula (XXVI) or (XXVII) is associated with a polyurethane via reaction of a isocyanate- terminated polyureth a (XXVIII):
• the end-capping reagent is 4-chlorobenzyl alcohol.
• At least one of the types of end-capping reagent includes an acid resulting in an end-capped polyurethane comprising an acid.
• the end-capping reagent comprising an acid comprises Formula (XXIX) or Formula (XXX):
• an end-capping reagent comprising Formula (XXIX) or (XXX) is associated with a polyurethane via reaction of a isocyanate-terminated polyurethane and an end-capping reagent comprising Formula (XXXI) or Formula (XXXII):
• the end-capping reagent is 3-aminopropane sulphonic acid.
• At least one of the types of end-capping reagent includes a silane resulting in an end-capped polyurethane comprising a silane.
• the end-capping reagent comprising a silane comprises Formula (XXXIII):
• each R 3 is the same or different and comprises -(CH 2 ) n - or -0-(CH2) n , where each n is the same or different and 1-4. In some embodiments, each n is the same or different and is 1 or 2. In some embodiments, R 3 comprises the reactive functional group.
• an end-capping reagent comprising Formula
• the end-capping reagent is 3-aminopropyl.trimethoxysilane.
• a first type and a second type of end-capping reagent are used.
• the first type of end-capping reagent comprises a cyclic carbonate and the second type of end-capping reagent comprises a pyrrolidone.
• Any suitable ratio of the first type of end-capping reagent to the second type of end-capping reagent may be utilized, for example, between about 1:2 and about 2:1, between about 1:1.5 and about 1.5:1, or about 1: 1.
• the end-capping group and/or reagent comprises an alkyl, an aryl, a cyano, a carbamate, and/or an acrylate group.
• the adhesive e.g., end-capped or isocyanate- terminated polyurethane
• the adhesive may be chain extended via reaction of the adhesive with a chain- extending reagent.
• the chain extension may be carried out under conditions suitable to obtain a targeted Mn of the adhesive and/or to obtain a targeted degree of functionality of the adhesive.
• the chain extension may be carried out via reaction of one or more of the side-groups of the adhesive.
• the reactive functional group is present on the chain-extending reagent.
• the molecular weight of a polyurethane or other polymer e.g., a polyol used to prepare the polyurethane.
• the molecular weight may be determined using gel permeation chromatography (GPC).
• the molecular weight (Mn) is determined using GPC calibrated using polystyrene standards.
• the chain-extending reagent may comprise a diol or a diamine.
• the chain-extending reagent can comprise a diamino compound.
• diamino compounds include compounds having the structure H2N-R 4 -NH2, wherein R 4 is optionally substituted arylene or optionally substituted alkylene.
• R 4 is -(CH2)p- wherein p is 1-10, or 2-8, or 3-7, or 4-6.
• the chain-extending reagent is hexamethylene diamine.
• R 4 comprises a reactive functional group.
• the chain-extending reagent is 1,3-diamino- 2-propanol (e.g., wherein the hydroxyl group is the reactive functional group).
• the chain-extending reagent comprises a diol compound (e.g., as described above).
• diol compounds include compounds having the structure HO-R 5 -OH, wherein R 5 is optionally substituted arylene or optionally substituted alkylene.
• R 5 is -(CH2)p- wherein p is 1-10, or 2-8, or 3-7, or 4-6.
• R 5 comprises a reactive functional group.
• the chain-extending reagent comprises the structure as in Formula (XXXV):
• m is 1-100. In some embodiments, m is at least 1, at least 2, at least 5, at least 10, at least 20, at least 50, or at least 75. In certain embodiments, m is less than or equal to 100, less than or equal to 75, less than or equal to 50, less than or equal to 20, less than or equal to 10, less than or equal to 5, or less than or equal to 2. Combinations of the above-referenced ranges are also possible (e.g., m is 1 to 100, m is 1 to 20, m is 10 to 50, m is 20 to 75, m is 50 to 100). Other ranges are also possible. Additional non-limiting examples of chain- extending reagents (e.g., diaminos and diols) comprising one or more functional groups are shown in FIG. 3.
• chain- extending reagents e.g., diaminos and diols
• At least a portion of the remaining reactive isocyanate groups following polymerization may be deactivated via addition of one or more terminating reagents such that the remaining isocyanate groups do not substantially react.
• the terminating reagent may be an end-capping reagent such that further reaction of the isocyanate group is terminated.
• acid groups present on the polyurethane may be neutralized via addition of one or more neutralizing reagents such that the polyurethane may be dispersed into water.
• neutralizing reagent include hydoxides (e.g., potassium hydroxide, lithium hydroxide) and tertiary amines (e.g., triethylamine, tributylamine, ethyldipropylamine, ethyldibutylamine, diethylpropylamine,
• the neutralizing reagent is triethylamine.
• basic groups present on the polyurethane may be neutralized via addition of one or more acidic neutralizing reagents such that the polyurethane may be dispersed into water, such as acetic acid.
• the amount of neutralizing reagent utilized may be between about 10 - 150 % (e.g., relative to the number of acid groups present on the polyurethane).
• adhesives e.g., as an aqueous dispersion, in an adhesive layer
• adhesives are generally comprise two or more cured moieties formed via reaction (i.e.
• the adhesive is formed via the reaction of at least one reactive functional group, at least two reactive functional groups, at least three reactive functional groups, or at least four reactive functional groups.
• Each reactive functional group may be the same or different and is generally capable of reacting with one or more curing species, described in more detail below.
• the reactive functional group has a particular dipole moment.
• the use of an adhesive formed via the reaction of one or more functional groups having a relatively high dipole moment may improve electro-optical performance of an electro-optic display compared to traditional adhesives.
• the dipole moment of a functional group may range between about 2 Debyes and about 6 Debyes.
• the dipole moment of a functional group is at least about 2 Debyes, at least about 2.5 Debyes, at least about 3 Debyes, at least about 4 Debyes, or at least about 5 Debyes.
• a cyclic carbonate group (e.g., comprising a structure as in Formula (XIV)) may have a dipole moment of about 5 Debyes
• a pyrrolidone (e.g., comprising a structure as in Formula (XVII)) may have a dipole moment of about 4 Debyes
• a nitrile (e.g., comprising a structure as in Formula (V)) may have a dipole moment of about 3.5 Debyes.
• the reactive functional group is generally present in the adhesive in an amount ranging between about 5 mole % and about 25 mole % versus the total adhesive composition. In some embodiments, the reactive functional group is present in the adhesive in an amount of at least about 5 mole %, at least about 10 mole %, at least about 15 mole %, or at least about 20 mole %. In certain embodiments, the reactive functional group is present in the adhesive in an amount of less than or equal to about 25 mole %, less than or equal to about 20 mole %, less than or equal to about 15 mole %, or less than or equal to about 10 mole %. Combinations of the above referenced ranges are also possible (e.g., between about 5 mole % and about 25 mole %).
• the adhesive is cured by the reaction of at least one reactive functional group with at least one curing species (e.g., during curing of the adhesive).
• the adhesive is cured by the reaction of a first reactive functional group with a first curing species (e.g., a first curing step to form a first cured moiety) and a second reactive functional group with a second curing species (e.g., a second curing step to form a second cured moiety).
• reaction of at least one reactive functional group with at least one curing species is not intended to encompass the reaction (e.g., the reaction of a diisocyanate and a secondary reagent such as a diol that forms the polyurethane) which forms the backbone of the adhesive prior to, for example, the addition of an end- capping reagent and/or a chain-extending reagent.
• the reaction of at least one reactive functional group with at least one curing species as described herein generally takes place during curing of the adhesive (e.g., such that the adhesive undergoes a change in one of a mechanical property (e.g., increased Young's elastic modulus), rheological property (e.g., increased viscosity), or the like).
• a mechanical property e.g., increased Young's elastic modulus
• rheological property e.g., increased viscosity
• one or more reactive functional groups may be present in the backbone of the adhesive, as described above, and may react with one or more curing species.
• the adhesive is cured by the reaction of a reactive functional group with a curing species such as a chain-extending reagent, a crosslinking reagent, or combinations thereof.
• the adhesive is cured by the reaction of a first reactive functional group with a curing species such as a second reactive functional group which maybe present on the backbone or on an end-capping reagent.
• the adhesive may be cured by thermoplastic drying of the adhesive material such that two or more reactive functional groups present on the adhesive material react.
• the curing species comprises a type of reactive functional group, as described above.
• the curing species may comprise a carboxylic acid group configured to react with a hydroxyl reactive functional group present on the adhesive material backbone or on an end-capping reagent.
• the reactive functional group comprises a carbon-carbon double bond or a carbon-carbon triple bond that reacts with a curing species such as sulfhydryl via a thiolene reaction.
• the reactive functional group is capable of reacting with a crosslinking reagent (i.e.
• the curing species comprises a crosslinker.
• suitable crosslinkers include monomers, oligomers, and polymers comprising polyfunctional reactive groups including amine, carbodiimide, epoxy, alcohol, thiol, isocyanate, or the like. Those skilled in the art would be capable of selecting suitable crosslinkers based upon the teachings of this specification.
• the curing species is a chain-extending reagent, as described above.
• the reactive functional group is capable of self-crosslinking and/or self-chain extending such as a mono-, di,- or tri-alkoxysilane.
• the curing species may comprise the same type of group as the reactive functional group (e.g., a silane) capable of reacting with the reactive functional group.
• the adhesive is formed by the reaction of one or more reactive functional groups present on the adhesive (e.g., polyurethane) with two or more crosslinkers.
• the adhesive is reacted with a first crosslinker (i.e. a first cure) and a second crosslinker (i.e. a second cure).
• the adhesive backbone is reacted with the first crosslinker during a first curing step such as drying and/or lamination of the adhesive.
• the adhesive is then reacted with the second crosslinker during a second curing step.
• the first crosslinker and the second crosslinker have different rates of crosslinking with the adhesive (e.g., with one or more reactive functional groups on the adhesive backbone). In certain embodiments, the first crosslinker and the second crosslinker have similar rates of crosslinking with the reactive functional groups present on the adhesive.
• the use of two or more crosslinkers provides desirable rheological properties to enable effective planarization of the adhesive during lamination and/or drying of the adhesive, and/or low adhesive layer coat weight.
• the mechanical properties of the adhesive can be controlled by the second crosslinker (i.e. during the second curing step).
• the long term stress reliability of the adhesive can be controlled by the second crosslinker.
• the functional reactive group reacts with the curing species in the presence of a stimulus such as electromagnetic radiation (e.g., visible light, UV light, etc.), an electron beam, increased temperature (e.g., such as utilized during solvent extraction or condensation reactions), a chemical compound (e.g., thiolene), and/or a crosslinker.
• a stimulus such as electromagnetic radiation (e.g., visible light, UV light, etc.), an electron beam, increased temperature (e.g., such as utilized during solvent extraction or condensation reactions), a chemical compound (e.g., thiolene), and/or a crosslinker.
• a stimulus such as electromagnetic radiation (e.g., visible light, UV light, etc.), an electron beam, increased temperature (e.g., such as utilized during solvent extraction or condensation reactions), a chemical compound (e.g., thiolene), and/or a crosslinker.
• Examples of types of reactive functional group reactions are shown in FIG. 4 including diamine or polyamine crosslinking, self- crosslinking
• the adhesive may comprise two or more types of adhesive materials (i.e. an adhesive hybrid).
• the adhesive may comprise a polyacrylate such as acrylic (e.g., configured to undergo a first cure by a thermoplastic drying) and a polyurethane (e.g., configured to undergo a second cure via reaction of the polyurethane with a reactive functional group present on the acrylate).
• a polyacrylate such as acrylic (e.g., configured to undergo a first cure by a thermoplastic drying) and a polyurethane (e.g., configured to undergo a second cure via reaction of the polyurethane with a reactive functional group present on the acrylate).
• the adhesive layer is positioned between the front plane electrode and the backplane electrode, which may apply the electric field needed to change the electrical state of the electro-optic material. That is to say, the electrical properties (e.g., resistivity, conductivity) of the adhesive may change the electric field applied to the electro-optic material. If the resistivity of the adhesive is too high, a substantial voltage drop may occur within the adhesive layer, requiring an increase in voltage across the electrodes. Increasing the voltage across the electrodes in this manner is undesirable, since it may increase the power consumption of the display, and may require the use of more complex and expensive control circuitry to handle the increased voltage involved.
• the electrical properties e.g., resistivity, conductivity
• the volume resistivity of the adhesive should not be too low, or lateral conduction of electric current through the continuous adhesive layer may cause undesirable cross-talk between adjacent electrodes. Furthermore, since the volume resistivity of most materials may decrease rapidly with increasing temperature, if the volume resistivity of the adhesive is too low, the performance of the assembly at temperatures substantially above room temperature is adversely affected.
• the volume resistivity of the adhesive may range between about 108 ohm- cm and about 1012 ohm cm, or between about 109 ohm- cm and about 1011 ohm- cm (e.g., at the operating temperature of the assembly around 20 °C). Other ranges of volume resistivity are also possible.
• the adhesive layer after curing may have a particular average coat weight.
• the adhesive layer can have an average coat weight ranging between about 2 g/m 2 and about 25 g/m 2 .
• the adhesive layer has an average coat weight of at least about 2 g/m 2 , at least about 4 g/m 2 , at least about 5 g/m 2 , at least about 8 g/m 2 , at least about 10 g/m 2 , at least about 15 g/m 2 , or at least about 20 g/m 2 .
• the adhesive layer has an average coat weight of less than or equal to about 25 g/m 2 , less than or equal to about 20 g/m 2 , less than or equal to about 15 g/m 2 , less than or equal to about 10 g/m 2 , less than or equal to about 8 g/m 2 , less than or equal to about 5 g/m 2 , or less than or equal to about 4 g/m 2 .
• Combinations of the above-referenced ranges are also possible (e.g., between about 2 g/m 2 and about 25 g/m 2 , between about 4 g/m 2 and about 10 g/m 2 , between about 5 g/m 2 and about 20 g/m 2 , between about 8 g/m 2 and about 25 g/m 2 ). Other ranges are also possible.
• the adhesive layer prior to curing may have a particular average wet coat thickness (e.g., such that the adhesive does not significantly alter electrical and/or optical properties of the electro-optic assembly).
• the adhesive layer can have an average wet coat thickness ranging between about 1 microns and about 100 microns, between about 1 microns and about 50 microns, or between about 5 microns and 25 microns.
• the adhesive layer may have an average wet coat thickness of less than about 25 microns, less than about 20 microns, less than about 15 microns, or less than about 12 microns, less than about 10 microns, or less than about 5 microns.
• the adhesive layer may have an average wet coat thickness between about 1 micron and about 50 microns, or between about 5 microns and 25 microns, or between about 5 microns and about 15 microns. In some embodiments (e.g., in embodiments where the adhesive is coated onto a layer and then laminated to an electro-optic material), the adhesive layer may have an average wet coat thickness between about 15 microns and 30 microns, or 20 microns and 25 microns. Other wet coat thicknesses are also possible.
• the adhesive layer may cover the entire underlying layer, or the adhesive layer may only cover a portion of the underlying layer.
• the adhesive layer may be applied as a laminate, which usually creates a thicker adhesive layer, or it may be applied as an overcoat, which usually creates a layer that is thinner than a laminate.
• the overcoat layer may utilize a dual curing system where a first cure occurs prior to overcoat such that the adhesive may be coated on the electro-optic material surface (or another surface) and a second cure sets the material after overcoating.
• the overcoat layer may be rough if the underlying surface is rough and only a thin layer is applied, or the overcoat layer may be used to planarize an underlying rough surface.
• Planarization may occur in a single step where the overcoat layer is applied to planarize the rough surface, for example, adding sufficient adhesive to fill in any voids and smooth the surface and minimally increase the overall thickness.
• planarization may occur in two steps where the overcoat layer is applied to minimally coat the rough surface and second coating is applied to planarize.
• the overcoat layer may be applied to a smooth surface.
• the electro-optic assembly comprises electro-optic material layer 125, capsules 150, and binder 160.
• the binder may also be an adhesive, as described above.
• the binder may be a polyurethane (e.g., comprising at least one type of end-group).
• the electro-optic assembly of the present invention may constitute a complete electro-optic display or only a sub-assembly of such a display (e.g., an electrophoretic display).
• a complete electro-optic display generally includes the presence of at least one, and normally two, electrodes to produce the electric field necessary to vary the optical state of the electro-optic material, although in some cases only one of the two electrodes may be a permanent part of the display, with the other electrode being in the form a movable stylus or similar instrument which can be moved over the display to write on the display.
• front plane electrode 130 comprises an electrode.
• backplane electrode 110 comprises an electrode.
• the electrode may be light-transmissive.
• the assembly may have the form of an active matrix display, with the first layer comprising a single continuous light-transmissive electrode extending across multiple pixels, and typically the whole, of the display.
• front plane electrode 130 and/or backplane electrode 110 comprises one or more electrode layers patterned to define the pixels of the display.
• one electrode layer may be patterned into elongate row electrodes and a second electrode layer may be patterned into elongate column electrodes running at right angles to the row electrodes, the pixels being defined by the intersections of the row and column electrodes.
• one electrode layer has the form of a single continuous electrode and a second electrode layer is patterned into a matrix of pixel electrodes, each of which defines one pixel of the display.
• electro-optic display which is intended for use with a stylus, print head or similar movable electrode separate from the display
• only one of the layers adjacent the electro-optic layer comprises an electrode, the layer on the opposed side of the electro-optic layer typically being a protective layer intended to prevent the movable electrode damaging the electro-optic layer.
• front plane electrode 130 may comprise a polymeric film or similar supporting layer (e.g., which may support the relatively thin light- transmissive electrode and protects the relatively fragile electrode from mechanical damage) and backplane electrode 110 comprises a support portion and a plurality of pixel electrodes (e.g., which define the individual pixels of the display).
• the backplane electrode may further comprise non-linear devices (e.g., thin film transistors) and/or other circuitry used to produce on the pixel electrodes the potentials needed to drive the display (e.g., to switch the various pixels to the optical states necessary to provide a desired image on the display).
• the electro-optic assembly may have the form of a front plane laminate.
• the front plane may comprise a light-transmissive electrically- conductive layer intended to form the front electrode of a final display.
• the front plane may comprise a polymeric film or similar supporting layer (e.g., which supports the relatively thin electrically-conductive layer and protect it from mechanical damage).
• the electro-optic assembly may include a release sheet, which is removed before the front plane laminate is laminated to the backplane electrode to form the final display.
• the electro-optic material layer comprises an encapsulated electrophoretic media.
• electro-optic material layer 125 comprises capsules 150 comprising encapsulated electrophoretic media and binder 160.
• the capsules may comprise encapsulated electrophoretic media comprising numerous small capsules, each of which itself comprises an internal phase containing electrophoretically-mobile particles (e.g., ink particles) suspended in a liquid suspending medium, and a capsule wall surrounding the internal phase.
• the capsules are held within a polymeric binder (e.g., binder 160) to form a coherent layer positioned between two electrodes (e.g., in the front plane electrode and the backplane electrode).
• a polymeric binder e.g., binder 160
• the walls surrounding the discrete microcapsules in an encapsulated electrophoretic medium may be replaced by a continuous phase, thus producing a so-called polymer-dispersed electrophoretic display, in which the electrophoretic medium comprises a plurality of discrete droplets of an electrophoretic fluid and a continuous phase of a polymeric material, and that the discrete droplets of electrophoretic fluid within such a polymer-dispersed electrophoretic display may be regarded as capsules or microcapsules even though no discrete capsule membrane is associated with each individual droplet.
• the electrophoretic medium comprises a plurality of capsules, each of the capsules comprising a capsule wall, a suspending fluid encapsulated within the capsule wall and a plurality of electrically-charged particles suspended in the suspending fluid and capable of moving there through on application of an electric field to the medium, the medium further comprising a binder surrounding the capsules.
• An encapsulated electrophoretic display typically does not suffer from the clustering and settling failure mode of traditional electrophoretic devices and provides further advantages, such as the ability to print or coat the display on a wide variety of flexible and rigid substrates.
• Use of the word "printing" is intended to include all forms of printing and coating, including, but without limitation: pre-metered coatings such as patch die coating, slot or extrusion coating, slide or cascade coating, curtain coating; roll coating such as knife over roll coating, forward and reverse roll coating; gravure coating; dip coating; spray coating; meniscus coating; spin coating; brush coating; air knife coating; silk screen printing processes; electrostatic printing processes; thermal printing processes; ink jet printing processes; electrophoretic deposition; and other similar techniques.
• the resulting display may be flexible.
• the display medium can be printed (e.g., using a variety of methods), the display itself can be made inexpensively.
• the electro-optic display is a "microcell electrophoretic display".
• the charged particles and the fluid are not encapsulated within microcapsules but instead may be retained within a plurality of cavities formed within a carrier medium (e.g., a polymeric film).
• electrophoretic media are often opaque (e.g., in many types of electrophoretic media, the particles substantially block transmission of visible light through the display) and operate in a reflective mode
• electrophoretic displays can be made to operate in a so-called “shutter mode" in which one display state is substantially opaque and one is light-transmissive.
• the adhesives described above may also be used in other electro-optic materials and electro-optic displays known in the art.
• the electro-optic material is a solid (e.g., a solid electro-optic display).
• the electro-optic material may comprise internal liquid- or gas-filled spaces.
• solid electro-optic displays includes encapsulated electrophoretic displays, encapsulated liquid crystal displays, and other types of displays.
• the electro-optic display is a rotating bichromal member (e.g., a rotating bichromal ball display.
• the display uses a large number of small bodies (typically spherical or cylindrical) which have two or more sections with differing optical characteristics, and an internal dipole. These bodies may be suspended within liquid-filled vacuoles within a matrix, the vacuoles being filled with liquid so that the bodies are free to rotate. The appearance of the display may be changed by applying an electric field thereto, thus rotating the bodies to various positions and varying which of the sections of the bodies is seen through a viewing surface.
• This type of electro- optic medium is typically bistable.
• bistable is used herein in its conventional meaning in the art to refer to displays comprising display elements having first and second display states differing in at least one optical property, and such that after any given element has been driven, by means of an addressing pulse of finite duration, to assume either its first or second display state, after the addressing pulse has terminated, that state may persist for at least several times, for example at least four times, the minimum duration of the addressing pulse required to change the state of the display element.
• some particle-based electrophoretic displays capable of gray scale are stable not only in their extreme black and white states but also in their intermediate gray states. This type of display is generally termed “multi- stable” rather than bistable, although for convenience the term “bistable” may be used herein to cover both bistable and multi- stable displays.
• electro-optic displays include an electro-optic display using an electrochromic medium, for example an electrochromic medium in the form of a nanochromic film comprising an electrode formed at least in part from a semi-conducting metal oxide and a plurality of dye molecules capable of reversible color change attached to the electrode; electro- wetting displays; and particle-based electrophoretic displays, in which a plurality of charged particles move through a suspending fluid under the influence of an electric field.
• an electrochromic medium for example an electrochromic medium in the form of a nanochromic film comprising an electrode formed at least in part from a semi-conducting metal oxide and a plurality of dye molecules capable of reversible color change attached to the electrode
• electro- wetting displays and particle-based electrophoretic displays, in which a plurality of charged particles move through a suspending fluid under the influence of an electric field.
• the adhesive layer may be formed using suitable techniques known in the art.
• the adhesive layer is formed as a film and then applied to the assembly, for example, via lamination.
• the adhesive e.g., comprising an end-capped polyurethane as described herein
• the adhesive may be coated onto a release layer or other substrate (e.g., a front or backplane electrode) and dried using techniques known in the art (e.g., via heating and/or exposure to vacuum).
• the substrate may comprise indium-tin-oxide (ITO) or a similar conductive coating (e.g., which acts as an electrode layer of the final display) on a plastic film or a release layer (e.g., comprising a flexible polymer).
• ITO indium-tin-oxide
• a similar conductive coating e.g., which acts as an electrode layer of the final display
• the adhesive material may be dispensed (e.g., via use of a die or slot coater) on the substrate.
• the thickness of the material may be controlled by flowability or amount of material pumped per square area of material.
• a backplane electrode containing an array of pixel electrodes and an appropriate arrangement of conductors to connect the pixel electrodes to drive circuitry, may be prepared.
• the substrate having the capsule/binder layer thereon may be laminated (e.g., via application of heat and use of a roll laminator) to the backplane electrode using an adhesive.
• a similar process can be used to prepare an electrophoretic display usable with a stylus or similar movable electrode by replacing the backplane electrode with a simple protective layer, such as a plastic film, over which the stylus or other movable electrode can slide.
• the backplane electrode is itself flexible and is prepared by printing the pixel electrodes and conductors on a plastic film or other flexible substrate.
• the adhesive material e.g., the isocyanate-terminated polyurethane
• the reactants e.g., diisocyante compound and secondary reagent such as a diol
• the synthesis of the adhesive may be conducted in an inert atmosphere (e.g., in the absence of water and in the presence of an inert gas such as nitrogen and/or argon).
• the reactants may be added in any particular order.
• the adhesive may be reacted with one or more additional reagents (e.g., end-capping reagent(s), chain-extending reagent(s), neutralizing reagent(s)).
• a dispersing medium such as water is added to the reaction mixture.
• the adhesive material may be dispersed in water (e.g., via addition of water to the reaction mixture or addition of the reaction mixture to water).
• the adhesive e.g., end-capped and/or neutralized
• the adhesive materials described herein can be cured. Curing may include, but not be limited to, the reaction of one or more reactive functional groups with one or more curing species (e.g., such that the adhesive is crosslinked, extended, entangled, etc.) as described herein.
• the adhesive may undergo two or more curing steps (e.g., a first cure and a second cure). That is to say, the adhesive may be cured by reacting a first reactive functional group with a first curing species (i.e. a first cure), and cured further by reacting a second reactive functional group with a second curing species (i.e. a second cure).
• the adhesive layer is formed by curing the adhesive such that a first reactive functional group reacts with a first curing species and then, subsequently, curing the adhesive such that a second reactive functional group reacts with a second curing species.
• the first and second cures may occur at substantially the same time or may occur at substantially different times.
• the first reactive functional group may be the same or different as the second reactive functional group.
• the first curing species may be the same or different as the second curing species.
• an adhesive having two or more cures may have low coat weights and/or thicknesses as compared to other adhesives, may impart a desirable rheological property in the adhesive (e.g., after the first cure and/or after the second cure), and/or may reduce or prevent the formation of voids and/or defects such that there are substantially no voids and/or defects are present in the adhesive layer after the first cure or after the second cure.
• the adhesive should generally have sufficient adhesive strength to bind the desired layer(s) to one another.
• the adhesive has sufficient adhesive strength to bind the desired layer(s) to one another after curing (e.g., after the first cure, after the second cure).
• the electro-optic assembly is flexible and, therefore, the adhesive may have sufficient flexibility not to introduce defects into the assembly when the assembly is flexed.
• Orange Peel may be determined using a wave-scan instrument to illuminate the specimen at a 60° angle to the surface, and measure the reflected light intensity collected at the equal but opposite angle from the specimen surface.
• Tc average crossover temperature
• the adhesive has an average crossover temperature of between about 0 °C and about 80 °C before a first cure and/or before a second cure.
• the average crossover temperature of the adhesive is less than about 80 °C, less than about 60 °C, less than about 40 °C, less than about 20 °C, or less than about 10 °C, before a first cure and/or before a second cure.
• the average crossover temperature may increase after a first cure (before a second cure) but remain between about 0 °C and about 80 °C (e.g., between about 20 °C and about 80 °C).
• An adhesive with an average crossover temperature as described above may flow and be easily laminated to one or more layers (e.g., an electrode layer, a release layer) and have substantially less defects as compared to an adhesive with a greater crossover temperature.
• curing e.g., crosslinking
• the adhesive will generally increase the crossover temperature and that, for example, a second cure may increase the crossover temperature to greater than 80 °C.
• the average crossover temperature of the adhesive after the second cure may be between about 80 °C and about 250 °C. In certain embodiments, the average crossover temperature of the adhesive after the second cure is at least about 80 °C, at least about 100 °C, at least about 150 °C, or at least about 200 °C. In some cases, the average crossover temperature of the adhesive after the second cure is less than or equal to about 250 °C, less than or equal to about 200 °C, less than or equal to about 150 °C, or less than or equal to about 100 °C. Combinations of the above-referenced ranges are also possible.
• Adhesive material may be dispensed (for example, by means of a die or slot coater) over the electrophoretic layer or on a release layer.
• the adhesive may be directly coated (e.g., via solution techniques) to the electro-optic material (or other underlying layer).
• the adhesive may then be dried using techniques known in the art (e.g., via heating and/or exposure to vacuum). Additional layers may then be applied on the outer surface of the adhesive.
• a dispersion comprising the adhesive material e.g., a polyurethane dispersed in water
• the adhesive material e.g., a polyurethane dispersed in water
• the thickness of the liquid material may be controlled, for example, via use of a doctor blade.
• the upper surface of the electro- optic material that the adhesive is being applied to may not be planar.
• the adhesive may be applied such that the final outer surface of the adhesive is planar or essentially planar.
• the adhesive material (e.g., comprising a first type of reactive functional group and a second type of reactive functional group) may be coated on at least a portion of a first layer (e.g., indium-tin-oxide (ITO) or a similar conductive coating on a plastic film, a release layer, an electro-optic material layer) and cured (i.e. a first cure) such that the first type of reactive functional group reacts with a first type of curing species (e.g., forming a first cured moiety).
• a first layer e.g., indium-tin-oxide (ITO) or a similar conductive coating on a plastic film, a release layer, an electro-optic material layer
• cured i.e. a first cure
• the adhesive may be contacted with a second layer (e.g., indium-tin-oxide (ITO) or a similar conductive coating on a plastic film, a release layer, an electro-optic material layer) and cured (i.e. a second cure) such that the second type of reactive functional group reacts with a second type of curing species (e.g., forming a second cured moiety).
• a second layer e.g., indium-tin-oxide (ITO) or a similar conductive coating on a plastic film, a release layer, an electro-optic material layer
• cured i.e. a second cure
• curing the adhesive e.g., the first cure, the second cure
• curing the adhesive generally adheres the adhesive layer to one or more layers.
• the adhesive may adhere to only one layer. In some cases, the adhesive adheres two layers together.
• the one or more layers may be removed (e.g., a release layer) prior to the second curing and a third layer (e.g., indium-tin-oxide (ITO) or a similar conductive coating on a plastic film, a release layer, an electro-optic material layer) may be contacted with the adhesive (i.e.
• a third layer e.g., indium-tin-oxide (ITO) or a similar conductive coating on a plastic film, a release layer, an electro-optic material layer
• the removed layer may have facilitated decreasing the roughness of the adhesive, and/or protected the adhesive layer (e.g., from physical damage, from contamination) prior to the second cure.
• One or more additional cures e.g., a third cure, a fourth cure, etc.
• the adhesive comprises three or more reactive functional groups that may be cured with three or more curing steps.
• the film of the adhesive on any substrate may be formed using techniques known in the art.
• the adhesive e.g., a polyurethane
• the adhesive is dispersed in water (or another solvent) and coated onto a layer (e.g., indium-tin-oxide (ITO) or a similar conductive coating on a plastic film, a release layer, an electro-optic material layer).
• ITO indium-tin-oxide
• a solution coating on a surface for example, spin coating, spray techniques, printed, die or slot coater, etc. Other additives may be present in the solution.
• the solution coating may then be dried using techniques known in the art (e.g., heat and/or vacuum), thereby forming the film.
• each reaction e.g., each curing stage
• room temperature e.g., about 25 °C, about 20 °C, between about 20 °C and about 25 °C, or the like.
• each reaction is carried out at temperatures below or above room
• each reaction is carried at a temperature between about 25 °C and about 140 °C, about 25 °C and about 75 °C, or between about 50 °C and about 100 °C.
• one or more of the reactions may be carried out in the presence of a solvent.
• the reactions may be carried out under neat conditions.
• solvents include hydrocarbons (e.g., pentane, hexane, heptane), halocarbons (e.g., chloroform, dichloromethane), ethers (e.g., diethylether, tetrahydrofuran (THF), 2-methoxyethyl ether (diglyme), and aromatic compounds (e.g., benzene, toluene).
• a reaction may also be carried out in water.
• aliphatic includes both saturated and unsaturated, nonaromatic, straight chain (i.e., unbranched), branched, acyclic, and cyclic (i.e., carbocyclic) hydrocarbons, which are optionally substituted with one or more functional groups.
• aliphatic is intended herein to include, but is not limited to, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, and cycloalkynyl moieties.
• alkyl includes straight, branched and cyclic alkyl groups.
• alkenyl alkynyl
• alkynyl alkenyl
• alkynyl alkynyl
• aliphatic is used to indicate those aliphatic groups (cyclic, acyclic, substituted, unsubstituted, branched or unbranched) having 1-20 carbon atoms.
• Aliphatic group substituents include, but are not limited to, any of the substituents described herein, that result in the formation of a stable moiety (e.g., aliphatic, alkyl, alkenyl, alkynyl, heteroaliphatic, heterocyclic, aryl, heteroaryl, acyl, oxo, imino, thiooxo, cyano, isocyano, amino, azido, nitro, hydroxyl, thiol, halo, aliphaticamino, heteroaliphaticamino, alkylamino, heteroalkylamino, arylamino, heteroarylamino, alkylaryl, arylalkyl, aliphaticoxy, heteroaliphaticoxy, alkyloxy, heteroalkyloxy, aryloxy, heteroaryloxy, aliphaticthioxy, heteroaliphaticthioxy, alkylthioxy, heteroalkylthioxy, arylthioxy, heteroarylthioxy,
• alkyl is given its ordinary meaning in the art and refers to the radical of saturated aliphatic groups, including straight-chain alkyl groups, branched-chain alkyl groups, cycloalkyl (alicyclic) groups, alkyl substituted cycloalkyl groups, and cycloalkyl substituted alkyl groups.
• the alkyl group may be a lower alkyl group, i.e., an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, or decyl).
• a straight chain or branched chain alkyl may have 30 or fewer carbon atoms in its backbone, and, in some cases, 20 or fewer.
• a straight chain or branched chain alkyl may have 12 or fewer carbon atoms in its backbone (e.g., C1-C12 for straight chain, C3-C12 for branched chain), 6 or fewer, or 4 or fewer.
• cycloalkyls may have from 3-10 carbon atoms in their ring structure, or 5, 6 or 7 carbons in the ring structure.
• alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, t-butyl, cyclobutyl, hexyl, and cyclochexyl.
• alkylene refers to a bivalent alkyl group.
• An "alkylene” group is a polymethylene group, i.e., -(03 ⁇ 4) ⁇ -, wherein z is a positive integer, e.g., from 1 to 20, from 1 to 10, from 1 to 6, from 1 to 4, from 1 to 3, from 1 to 2, or from 2 to 3.
• a substituted alkylene chain is a polymethylene group in which one or more methylene hydrogen atoms are replaced with a substituent. Suitable substituents include those described herein for a substituted aliphatic group.
• a bivalent carbocycle is “carbocyclylene”
• a bivalent aryl ring is “arylene”
• a bivalent benzene ring is “phenylene”
• a bivalent heterocycle is
• heterocyclylene a bivalent heteroaryl ring is “heteroarylene”
• a bivalent alkyl chain is “alkylene”
• a bivalent alkenyl chain is “alkenylene”
• a bivalent alkynyl chain is “alkynylene”
• a bivalent heteroalkyl chain is "heteroalkylene”
• a bivalent heteroalkenyl chain is
• heteroalkenylene a bivalent heteroalkynyl chain is “heteroalkynylene”, and so forth.
• alkenyl and alkynyl are given their ordinary meaning in the art and refer to unsaturated aliphatic groups analogous in length and possible substitution to the alkyls described above, but that contain at least one double or triple bond respectively.
• the alkyl, alkenyl and alkynyl groups employed in the invention contain 1-20 aliphatic carbon atoms. In certain other embodiments, the alkyl, alkenyl, and alkynyl groups employed in the invention contain 1-10 aliphatic carbon atoms. In yet other embodiments, the alkyl, alkenyl, and alkynyl groups employed in the invention contain 1-8 aliphatic carbon atoms. In still other embodiments, the alkyl, alkenyl, and alkynyl groups employed in the invention contain 1-6 aliphatic carbon atoms.
• the alkyl, alkenyl, and alkynyl groups employed in the invention contain 1-4 carbon atoms.
• Illustrative aliphatic groups thus include, but are not limited to, for example, methyl, ethyl, n-propyl, isopropyl, allyl, n-butyl, sec -butyl, isobutyl, t-butyl, n-pentyl, sec- pentyl, isopentyl, t-pentyl, n-hexyl, sec -hexyl, moieties and the like, which again, may bear one or more substituents.
• Alkenyl groups include, but are not limited to, for example, ethenyl, propenyl, butenyl, l-methyl-2-buten-l-yl, and the like.
• Representative alkynyl groups include, but are not limited to, ethynyl, 2-propynyl (propargyl), 1-propynyl and the like.
• cycloalkyl refers specifically to groups having three to ten, preferably three to seven carbon atoms.
• Suitable cycloalkyls include, but are not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and the like, which, as in the case of other aliphatic, heteroaliphatic, or heterocyclic moieties, may optionally be substituted with substituents including, but not limited to aliphatic; heteroaliphatic; aryl; heteroaryl; arylalkyl; heteroarylalkyl; alkoxy; aryloxy; heteroalkoxy; heteroaryloxy;
• heteroaliphatic refers to an aliphatic moiety, as defined herein, which includes both saturated and unsaturated, nonaromatic, straight chain (i.e., unbranched), branched, acyclic, cyclic (i.e., heterocyclic), or polycyclic hydrocarbons, which are optionally substituted with one or more functional groups, and that contain one or more oxygen, sulfur, nitrogen, phosphorus, or silicon atoms, e.g., in place of carbon atoms.
• heteroaliphatic moieties are substituted by independent replacement of one or more of the hydrogen atoms thereon with one or more substituents.
• heteroaliphatic is intended herein to include, but is not limited to, heteroalkyl, heteroalkenyl, heteroalkynyl, heterocycloalkyl,
• heterocycloalkenyl and heterocycloalkynyl moieties.
• heteroaliphatic includes the terms “heteroalkyl,” “heteroalkenyl”, “heteroalkynyl”, and the like.
• heteroalkyl encompass both substituted and unsubstituted groups.
• heteroaliphatic is used to indicate those heteroaliphatic groups (cyclic, acyclic, substituted, unsubstituted, branched or unbranched) having 1-20 carbon atoms.
• Heteroaliphatic group substituents include, but are not limited to, any of the substituents described herein, that result in the formation of a stable moiety (e.g., aliphatic, alkyl, alkenyl, alkynyl, heteroaliphatic, heterocyclic, aryl, heteroaryl, acyl, sulfinyl, sulfonyl, oxo, imino, thiooxo, cyano, isocyano, amino, azido, nitro, hydroxyl, thiol, halo, aliphaticamino, heteroaliphaticamino, alkylamino, heteroalkylamino, arylamino, heteroarylamino, alkylaryl, arylalkyl, aliphaticoxy, heteroaliphaticoxy, alkyloxy, heteroalkyloxy, aryloxy, heteroaryloxy, aliphaticthioxy, heteroaliphaticthioxy, alkylthioxy, hetero
• heteroalkyl is given its ordinary meaning in the art and refers to an alkyl group as described herein in which one or more carbon atoms is replaced by a heteroatom. Suitable heteroatoms include oxygen, sulfur, nitrogen, phosphorus, and the like. Examples of heteroalkyl groups include, but are not limited to, alkoxy, amino, thioester, poly(ethylene glycol), and alkyl-substituted amino.
• heteroalkenyl and “heteroalkynyl” are given their ordinary meaning in the art and refer to unsaturated aliphatic groups analogous in length and possible substitution to the heteroalkyls described above, but that contain at least one double or triple bond respectively.
• substituents of the above-described aliphatic (and other) moieties of compounds of the invention include, but are not limited to aliphatic;
• aryl is given its ordinary meaning in the art and refers to aromatic carbocyclic groups, optionally substituted, having a single ring (e.g., phenyl), multiple rings (e.g., biphenyl), or multiple fused rings in which at least one is aromatic (e.g., 1,2,3,4- tetrahydronaphthyl, naphthyl, anthryl, or phenanthryl). That is, at least one ring may have a conjugated pi electron system, while other, adjoining rings can be cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and/or heterocyclyls.
• the aryl group may be optionally substituted, as described herein.
• Substituents include, but are not limited to, any of the previously mentioned substituents, i.e., the substituents recited for aliphatic moieties, or for other moieties as disclosed herein, resulting in the formation of a stable compound.
• an aryl group is a stable mono- or polycyclic unsaturated moiety having preferably 3-14 carbon atoms, each of which may be substituted or unsubstituted.
• Carbocyclic aryl groups refer to aryl groups wherein the ring atoms on the aromatic ring are carbon atoms.
• Carbocyclic aryl groups include monocyclic carbocyclic aryl groups and polycyclic or fused compounds (e.g., two or more adjacent ring atoms are common to two adjoining rings) such as naphthyl groups.
• heteroaryl is given its ordinary meaning in the art and refers to aryl groups comprising at least one heteroatom as a ring atom.
• a “heteroaryl” is a stable heterocyclic or polyheterocyclic unsaturated moiety having preferably 3-14 carbon atoms, each of which may be substituted or unsubstituted. Substituents include, but are not limited to, any of the previously mentioned substituents, i.e., the substituents recited for aliphatic moieties, or for other moieties as disclosed herein, resulting in the formation of a stable compound.
• a heteroaryl is a cyclic aromatic radical having from five to ten ring atoms of which one ring atom is selected from S, O, and N; zero, one, or two ring atoms are additional heteroatoms independently selected from S, O, and N; and the remaining ring atoms are carbon, the radical being joined to the rest of the molecule via any of the ring atoms, such as, for example, pyridyl, pyrazinyl, pyrimidinyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isooxazolyl, thiadiazolyl,oxadiazolyl, thiophenyl, furanyl, quinolinyl, isoquinolinyl, and the like.
• aryl and heteroaryl moieties may be attached via an alkyl or heteroalkyl moiety and thus also include -(alkyl)aryl, -(heteroalkyl)aryl, -(heteroalkyl)heteroaryl, and -(heteroalkyl)heteroaryl moieties.
• aryl or heteroaryl moieties and "aryl, heteroaryl, -(alkyl)aryl, - (heteroalkyl)aryl, -(heteroalkyl)heteroaryl, and -(heteroalkyl)heteroaryl” are interchangeable.
• Substituents include, but are not limited to, any of the previously mentioned substituents, i.e., the substituents recited for aliphatic moieties, or for other moieties as disclosed herein, resulting in the formation of a stable compound.
• aryl and heteroaryl groups can be unsubstituted or substituted, wherein substitution includes replacement of one or more of the hydrogen atoms thereon independently with any one or more of the following moieties including, but not limited to: aliphatic; alicyclic; heteroaliphatic; heterocyclic; aromatic; heteroaromatic; aryl; heteroaryl; alkylaryl; heteroalkylaryl; alkylheteroaryl;
• heteroalkylheteroaryl alkoxy; aryloxy; heteroalkoxy; heteroaryloxy; alkylthio; arylthio; heteroalkylthio; heteroarylthio; F; CI; Br; I; -OH; -N0 2 ; -CN; -CF 3 ; -CHF 2 ; -CH 2 F; -CH2CF3; -CHCI2; -CH2OH; -CH2CH2OH; -CH2NH2; -CH2SO2CH3; -C(0)Rx; -C0 2 (Rx); -CON(Rx) 2 ; -OC(0)Rx; -OC0 2 Rx; -OCON(Rx) 2 ; -N(Rx) 2 ; -S(0) 2 Rx; -NRx(CO)Rx wherein each occurrence of Rx independently includes, but is not limited to, aliphatic, alicyclic, heteroaliphatic, heterocyclic,
• any two adjacent groups taken together may represent a 4, 5, 6, or 7-membered substituted or unsubstituted alicyclic or heterocyclic moiety. Additional examples of generally applicable substituents are illustrated by the specific embodiments described herein.
• substituent When more than one position in any given structure may be substituted with more than one substituent selected from a specified group, the substituent may be either the same or different at every position. It will be understood that “substituted” also includes that the substitution results in a stable compound, e.g., which does not spontaneously undergo transformation such as by rearrangement, cyclization, elimination, etc. In some cases, “substituted” may generally refer to replacement of a hydrogen with a substituent as described herein. However, “substituted,” as used herein, does not encompass replacement and/or alteration of a key functional group by which a molecule is identified, e.g., such that the "substituted" functional group becomes, through substitution, a different functional group.
• a "substituted phenyl group” must still comprise the phenyl moiety and cannot be modified by substitution, in this definition, to become, e.g., a pyridine ring.
• the permissible substituents include acyclic and cyclic, branched and unbranched, carbocyclic and heterocyclic, aromatic and nonaromatic substituents of organic compounds.
• Illustrative substituents include, for example, those described herein.
• the permissible substituents can be one or more and the same or different for appropriate organic compounds.
• the heteroatoms such as nitrogen may have hydrogen substituents and/or any permissible substituents of organic compounds described herein which satisfy the valences of the heteroatoms. Furthermore, this invention is not intended to be limited in any manner by the permissible substituents of organic compounds.
• substituents include, but are not limited to, halogen, azide, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, alkoxyl, amino, nitro, sulfhydryl, imino, amido, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamide, ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromatic moieties, - CF3, -CN, aryl, aryloxy, perhaloalkoxy, aralkoxy, heteroaryl, heteroaryloxy, heteroarylalkyl, heteroaralkoxy, azido, amino, halide, alkylthio, oxo, acylalkyl, carboxy esters, carboxamido, acyloxy,
• Example 1 Synthesis of a polyurethane dispersion with chain extension using a non-stoichiometric amount of end group monomer, lower solvent content, catalyzed with chain extension after dispersion - with Glycerin Carbonate (CCARB) End Group (EG) (Adhesive A)
• NMP N-Methyl- 2-pyrrolidone
• Example 2 Synthesis of a polyurethane dispersion using a mixture of end group monomers, catalyzed, with chain extension after dispersion - Glycerin Carbonate / 3-aminopropyl trimethoxysilane (Adhesive B)
• TEA 3.71 g was added and after 15 minutes, the prepolymer was dispersed into 202 g DIW at ⁇ 39°C over 10 minutes. After an additional 5 minutes mixing at 1000 rpm, HMDA (2.09 g) in DIW (15.0 g) and 3- aminopropyl trimethoxysilane (2.216 g) were separately added dropwise to the dispersion over 10 minutes. After an additional 60 minutes a clear, translucent dispersion was isolated.
• TEA TEA
• HMDA HMDA
• DfW DfW
• 3-aminopropyl trimethoxysilane 3.13 g
• Example 6 Synthesis of a polyurethane dispersion with chain extension after dispersion using a non-stoichiometric amount of end group monomer in solvent, catalyzed - Glycerin Carbonate EG (Adhesive F) [Para 168] To a 1 1, 3-necked flask was added 31.82 g H12MDI (4,4'- Methylenebis(cyclohexyl isocyanate), hydrogenated MDI), 5.79 g of DMPA
• the prepolymer was added over 10 minutes followed by an additional 5 minutes mixing at 1000 rpm.
• a 35.4 % solution of HMDA in DrW (4.61 g) was diluted with an additional 10.02 g DIW and added dropwise to the dispersion over 15 minutes. After an additional 30 minutes a clear, slightly opaque dispersion was isolated.
• Example 7 Synthesis of a polyurethane dispersion using a mixture of end group monomers, catalyzed, with chain extension after dispersion - Glycerin Carbonate / 2-Hydroxyethyl pyrrolidone (HEP) EG (Adhesive G)
• H12MDI 4,4'-Methylenebis(cyclohexyl isocyanate), hydrogenated MDI
• 0.060 g of dibutyltin dilaurate was then added and the mixture was heated to 75 - 76°C for 5 hours, after which 4.828 g of a mix of glycerin carbonate (3.35 g) and 2-hydroxyethyl pyrrolidone (3.653 g) was added and stirred for an additional 3.5 hours.
• TEA (3.61 g) was added and after 15 minutes, the prepolymer was dispersed into 202 g DrW at ⁇ 39°C over 15 minutes followed by an additional 5 minutes mixing at 750 rpm.
• HMDA (2.09 g) in water (10.0 g) DrW and added dropwise to the dispersion over 10 minutes. After an additional 60 minutes, the clear, translucent dispersion was isolated.
• Example 8 Synthesis of a polyurethane dispersion used a stoichiometric mixture of end group monomers - Glycerin Carbonate / 2-Hydroxyethyl pyrrolidone (Adhesive H)
• the temperature was dropped to 55°C and mixed for an additional 20 hours.
• the temperature of the reaction was increased to 75 °C at which time TEA (4.58 g) was added.
• TEA 4.58 g
• the prepolymer was dispersed into 310 g DIW at ⁇ 39°C.
• the prepolymer was added over 30 minutes followed mixing overnight at ambient temperature. A clear, translucent dispersion was isolated.
• the temperature was decreased to 80°C and 10.60 g of a mix of glycerin carbonate (4.378 g) and 2-hydroxyethyl pyrrolidone (9.552 g) was added and stirred for an additional 1 hour. The temperature was dropped to 55°C and mixed for an additional 20 hours. The temperature of the reaction was decreased to 70°C and mixed overnight for an additional 21 hours.
• TEA 7.15 g was added and after 15 minutes, the prepolymer was dispersed into 462 g DrW at 50°C. The prepolymer was added over 70 minutes at which time the temperature was increased to 65 °C over 1.5 hours. After overnight mixing at ambient temperature, a clear, translucent dispersion was isolated.
• Example 10 Synthesis of a polyurethane dispersion using a non- stoichiometric mixture of end group monomers, catalyzed, with chain extension after dispersion - 2-hydroxyethylpyrrolidone / 3-aminopropyl trimethoxysilane (Adhesive L) [Para 176] To a 1 1, 3-necked flask under a nitrogen atmosphere was added 74.818 g polypropylene glycol) (Mn ⁇ 2,000), 8.515 g of Ymer N120 (Perstorp), and 4.054 g of DMPA (dimethylolpropionic acid).
• the temperature was decreased to 80°C and 16.84 g of a mix of glycerin carbonate (6.656 g) and 2-hydroxyethyl pyrrolidone (14.419 g) was added and stirred for an additional 16 hours.
• the temperature was decreased to 78°C and TEA (10.54 g) was added.
• the prepolymer was dispersed into 625 g DIW at 40C over 30 minutes, followed by chain extension using a mix of HMDA (5.51 g) in DrW (10.8 g) over an additional 10 minutes.
• the reaction temperature was increased to 55 °C for 1 hour, after which time heating was terminated and the dispersion mixed under ambient conditions overnight to yield a clear, semi-translucent product.
• Example 15 Example 15. General Overcoating Process and Test Display Structures
• Example 188 This example illustrates the general overcoating process and test display structures used in the subsequent examples, unless indicated otherwise.
• Previously coated and dried ink either on a first release substrate (for 3-layer such as shown in FIG. ID) or electrode substrate (for 2-layer such as shown in FIG. 1C), was coated with adhesive fluid (prepared by mixing the corresponding polyurethane dispersion with a specified amount of crosslinker(s)) to a specified dry coat weight using either a slot- die or linear bar coater.
• adhesive fluid prepared by mixing the corresponding polyurethane dispersion with a specified amount of crosslinker(s)
• the ink-adhesive coating was then oven dried at a specified temperature and residence time, followed by lamination to either an electrode substrate (for 3 -layer) or a release substrate (for 2-layer).
• the first release substrate was removed from the ink surface which is then laminated to a smooth side laminate (SSL) adhesive (e.g., adhesive layer 140 in FIG. ID).
• SSL smooth side laminate
• Both intermediate structures (2-layer and 3-layer) are then processed into test display structures by cutting appropriately sized sections, removing the remaining release backing and laminating to the appropriate backplane electrode.
• Test display conditioning was typically carried out after 25 °C and 50% relative humidity (RH) conditioning, unless alternate conditions are required.
• Table 1 shows to EO states of cyclic carbonate modified polyurethanes overcoated to one or more types of ink layers compared with a comparative laminate control (an aqueous polyurethane dispersion) laminated to an ink layer in a 3-layer structure.
• Overcoat wet film thicknesses were ⁇ 4 mil corresponding to a coat weight of ⁇ 25 g/m 2 .
• the 3-layer pixels were conditioned at 25°C and 50%RH.
• Adhesive C contains a lower level of cyclic carbonate functionality than Adhesive B. It was observed that significantly improved white state (WS), dark state (DS) and dynamic range (DR) L* values were obtained for the experimental adhesives when compared to the comparative laminate pixel. While the overall dynamic range achieved for the adhesives and control adhesive in Table 1 were relatively similar, it is possible to manipulate the WS and DS by changing the level of cyclic carbonate as indicated.
• FIGS. 5A-5B show adjusted 30s image stability traces of experimental polyurethanes overcoated to an ink layer compared to the control adhesive laminated over an ink layer.
• the 3-layer pixels were conditioned at 25 °C and 50%RH.
• FIGS. 5A-5B illustrate the effect the level of cyclic carbonate functionality has on the WS and DS 30s image stability.
• Both adhesives lead to minimal WS kickback and have either stable WS L* (FIG. 5B), or minimal WS L* improvement, simultaneous with improved L* values. Similar improved behavior was observed for the DS L* stability, although the increase was slightly greater then observed for the WS.
• FIG. 8 illustrates the effect of pyrrolidone versus cyclic carbonate end-capping groups. Both functional groups are 5-membered heterocycles with either 1 or 2 carbon atoms separating the ring from the oxygen bonded to the polyurethane chain. At equimolar levels of incorporation into the polyurethane backbone, significantly better image stability was observed for the cyclic carbonate containing polyurethane, clearly illustrating the effect of functionality type.
• FIG. 9 shows the 240 ms WS L* pulse trace for adhesive M overcoated to an ink layer compared with the comparative laminate laminated to the same ink.
• Adhesive M incorporates cyclic carbonate functionality as well as acid functionality for curing. Both adhesives were coated to ⁇ 25 g/m2 utilizing 5 mil thickness electrode. A 3 L* boost in WS was observed for the overcoated ink (with equal DS L* traces).
• Example 18 Direct to ITO ink structures.
• Table 3 shows initial dynamic range 5L* (relative to the comparative laminate) that vary with end group modification. It was observed that comparable initial properties are obtained with carbonate modified polyurethanes relative to the comparative (Control) laminated ink.
• Examples 20-23 generally relate to low coat weight adhesive films.
• Table 5 lists coat weight, void count and orange peel for ink-adhesive- electrode structures in which adhesive N, containing carboxylic acid, cyclic carbonate and acrylate functionality, was overcoated to an ink layer on a release substrate by using a linear bar coater.
• a dry coat weight of 6 g/m2 (approximately 1 mil wet coat thickness) was achieved by using a 30% solids aqueous adhesive formulation.
• orange peel values are within the range typically observed for current commercial products that have adhesive coat weights of 25 g/m2.
• the characteristics of the adhesive were selected to balance adhesive Tc (e.g., to influence how the material flows into the surface of the ink where thinner films require reduced amounts of adhesive, generally requiring lower adhesive Tc values in order to planarize the electro-optic layer before curing), the extent of crosslinking (acid-carbodiimide), as well as solvent evaporation during the first cure to enable flow with filling of the rough ink surface and subsequent void-free lamination (e.g., after the second cure) to both 5 mil and 1 mil electrode substrate.
• adhesive Tc e.g., to influence how the material flows into the surface of the ink where thinner films require reduced amounts of adhesive, generally requiring lower adhesive Tc values in order to planarize the electro-optic layer before curing
• the extent of crosslinking as well as solvent evaporation during the first cure to enable flow with filling of the rough ink surface and subsequent void-free lamination (e.g., after the second cure) to both 5 mil and 1 mil electrode substrate.
• Electrode thickness Overcoat Weight (g/m 2 ) Void Count per Size Range ( ⁇ ) Orange Peel INc)
• Table 5 shows the coat weight, void count and orange peel values for lamination of 5 mil and 1 mil electrode to adhesive N overcoated to an ink layer open ink-on- release.
• Table 6 show 25 °C electro-optical data for adhesive M overcoated to prototype ink on release at a low and high wet film build illustrating the impact of electro- optically active functionality and a low coat weight adhesive. 3 -Layer, pixels were cured at 50°C / 50% RH and reconditioned to 25 °C / 50% RH prior to measurement.
• the adhesive was applied to either an electrode substrate (for example, a 3 -layer structure) or to a release substrate (for example, a 2-layer structure) followed by lamination to the ink surface. Secondary curing to achieve final mechanical and electro-optical property development to both interfaces was then carried out.
• Adhesives B (acid, cyclic carbonate, silane functionality) and Adhesive L (acid, pyrrolidone, silane functionality), both mixed with a carbodiimide crosslinker (for stage I curing (the first cure), was coated to release substrate at 1.5 mil wet film build (approximately 7 - 9 g/m2 dry adhesive), dried in a cross draft oven and laminated to prototype ink on 1 mil electrode substrate. The adhesive surface was directly laminated to a carbon backplane, or to commercial SSL, which was then laminated to a carbon backplane. Stage II curing (the second cure) is afforded by the incorporated trimethoxysilane functionality via condensation mechanisms.
• open ink on 1 mil electrode substrate was laminated to SSL (2 layers each at 5 g/m2 adhesive weight; 10 g/m2 total coat weight).
• the SSL was minimally crosslinked thereby allowing a direct comparison of adhesive rheology and effects of dual curing on lamination quality. Some void formation was evident (indirectly observed via switching effects) in the comparative example whereas the pixels with adhesive B exhibited no evidence of lamination voids when switched.
• Table 7 shows initial and 30s L* values for 2- or 3-layer DTI pixels of B and Adhesive L adhesive laminated to prototype ink on 1 mil electrode substrate, compared with 2-layer pixels made using two layers of commercial SSL (at 5 g/m2 adhesive weight; 10 g/m2 total adhesive coat weight) laminated to prototype ink on 1 mil electrode.
• Experimental adhesives were coated to ⁇ 1.5 mil wet bar height on 1 mil electrode, corresponding to ⁇ 7 - 9 g/m2 dry adhesive.
• FIG. 12 The rheology profile of a hybrid adhesive A is shown in FIG. 12. Both pre- cure and post-cure curves are illustrated.
• the shear storage modulus (G') and shear loss modulus (G") are plotted as a function of temperature for stage I (thermoplastic dry) and stage II (acid-epoxy covalent crosslinking) cured adhesives.
• stage I thermoplastic dry
• stage II acid-epoxy covalent crosslinking
• the crossover temperature (Tc) of polyurethanes i.e., the temperature at which tan delta (ratio of loss modulus to storage modulus) is equal to 1 and the material begins to exhibit more viscous flow, is utilized to estimate the relative ease with which the adhesive planarizes the ink surface during drying and lamination.
• Tc The crossover temperature
• tan delta ratio of loss modulus to storage modulus
• hybrid adhesive A has a Tc approximately 10-15 °C higher than the parent, unmodified polyurethane, making it generally suitable for use as a planarization adhesive at low coat weights. Improved rheology was achieved with the hybrid adhesive, whereas a significantly higher coat weight adhesive layer was required in order to efficiently planarize the ink surface using the commercial adhesive.
• hybrid adhesive A was conducted by overcoating the adhesive fluid to open ink, drying in a heated oven (stage I cure), laminating a release substrate and subsequent stage II curing (chemical crosslinking) enabling the formation of an ink-adhesive coating layer that was relatively very thin (overall ink-adhesive thickness was about 23-24 microns) with a very low level of void defects.
• stage I cure stage I cure
• stage II curing chemical crosslinking
• FIGS. 13-14 are SEM micrographs of a cross- section of a 2-layer ink-adhesive stack with hybrid adhesive A coated to 8 g/m2 (dry coat weight) demonstrating planarization and relatively defect free (voids) adhesive-ink interface and illustrating the overall thickness of the ink-adhesive coating layer.
• High temperature stress testing of a test glass display made from this front plane laminate (FPL) did not result in any defect formation confirming sufficient mechanical property development after stage II curing.
• Example 23 Polyurethane adhesive with multiple crosslinking reagents
• a relatively low Tc polyurethane is combined with two different crosslinking reagents that differ in relative rates of crosslinking with reactive functionality on the polyurethane backbone.
• Stage I crosslinking was achieved during drying and lamination of adhesive application providing desirable rheology to enable subsequent processing steps.
• Stage II crosslinking largely occurred during the cure conditioning cycle of the FPL.
• FIG. 15 illustrates the use of carbodiimide and epoxy crosslinkers with polyurethane (PU) that have significantly different crosslinking rates.
• FIGS. 17A-17B are SEM micrographs of a cross-section of a 2-layer ink-adhesive stack with Adhesive J coated at 7 g/m 2 demonstrating planarization and relatively defect free (voids) adhesive-ink interface and illustrating the overall thickness of the ink-adhesive coating layer. High temperature stress testing of a test glass display made from this FPL did not result in any defect formation confirming sufficient mechanical property development after crosslinking.
• the adhesive used a synthesis of a polyurethane dispersion with a mixture of end group monomers - Glycerin Carbonate / 2-Hydroxyethyl pyrrolidone such as Adhesive J.
• the dual (covalent) crosslinking cure utilized the carboxylic acid functionality on the polyurethane to react with carbodiimide and epoxy crosslinkers.
• the following amounts of crosslinkers were used with Adhesive J:
• Sample I Sample I: 4.8 wt. % carbodiimide crosslinker (single cure)
• a reference to "A and/or B,” when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A without B (optionally including elements other than B); in another embodiment, to B without A (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

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